Difference between revisions of "Bicycle" - New World Encyclopedia

From New World Encyclopedia
(added credit and category tags)
Line 1: Line 1:
 +
{{Claimed}}
 
{{otheruses}}
 
{{otheruses}}
[[Image:Kusuma bike large.jpg|thumb|300px|This ''[[Racing bicycle|racing bicycle]]'' is built using lightweight, shaped aluminium tubing and [[Graphite-reinforced plastic|carbon fiber]] stays and forks.  It sports a drop handlebar and thin tires and wheels for efficiency and aerodynamics]]
+
[[Image:Kusuma bike large.jpg|thumb|300px|This ''[[racing bicycle]]'' is built using lightweight, shaped [[aluminium]] tubing and [[Graphite-reinforced plastic|carbon fiber]] stays and forks.  It sports a drop handlebar and thin tires and wheels for efficiency and aerodynamics.]]
 +
[[Image:utility bicycle.jpg|thumb|300px|Dutch utility bicycle featuring rear internal hub brake, chaincase and mudguards, kickstand for parking, permanently attached dynamo-powered lamps and touring handlebars.]]
 +
[[Image:Mountainbike.jpg|thumb|300px|This ''[[Mountain bike|mountain bicycle]]'' features oversized tires, a full-suspension frame, two disc brakes and handlebars oriented perpendicular to the bike's axis]]
  
[[Image:utility bicycle.jpg|thumb|300px|Dutch utility bicycle featuring rear internal hub brake, chaincase and mudguards, kickstand for parking, permanently attached dynamo-powered lamps and touring handlebars.]]
+
A '''bicycle''', or '''bike''', is a [[bicycle pedal|pedal-driven]], [[human-powered transport|human-powered vehicle]] with two [[bicycle wheel|wheels]] attached to a [[bicycle frame|frame]], one behind the other.
 +
 
 +
First introduced in nineteenth-century Europe, bicycles now number over one billion worldwide,<ref>DidYouKnow.cd. [http://www.didyouknow.cd/bicycles.htm There are about a billion bicycles in the world.] Retrieved 30 July 2006.</ref> providing the principal means of transportation in many regions, notably China and the Netherlands. They are also a popular form of [[recreation]], and have been adapted for use in many other fields of human activity, including children's [[toy]]s, adult [[fitness]], [[military]] and [[police]] applications, [[courier]] services, and cycle [[sports]].
  
A '''bicycle''', or '''bike''', is a pedal-driven [[land vehicle]] with two [[wheel]]s attached to a frame, one behind the other. First introduced in [[19th century|19th-century]] [[Europe]], bicycles evolved quickly into their familiar, current design. Numbering over 1,000,000,000 in the world today, bicycles provide the principal means of transportation in many regions and a popular form of recreation and transport in others.
+
The basic shape and configuration of a typical bicycle's frame, wheels, pedals, saddle, and handlebars have hardly changed since the first chain-driven model was developed around 1885,<ref name="herlihy">{{cite book
 +
| title = Bicycle: the history
 +
| last = Herlihy
 +
| first = David V.
 +
| year = 2004
 +
| publisher = Yale University Press
 +
| id = ISBN 0-300-10418-9
 +
| pages = 200-250}}</ref>
 +
although many important details have since been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for individuals who pursue a particular type of [[cycling]].  
  
The bicycle has affected history considerably in both the cultural and industrial realms. In its early years, bicycle construction drew on pre-existing technologies; more recently, bicycle technology has contributed, in turn, to other, newer areas. Beyond recreation and transportation, bicycles have been adapted for use in many occupations, including the military, local policing, courier services, and sports.  A recurrent theme in bicycling has been the tension between bicyclists and drivers of [[motor vehicle]]s, each group of whom argues for its fair share of the world's roadways.  According to members of [[Critical Mass]], a bicycle activist group, "We aren't blocking traffic, we ''are'' traffic!"
+
The bicycle has affected history considerably, in both the cultural and industrial realms. In its early years, bicycle construction drew on pre-existing technologies; more recently, bicycle technology has, in turn, contributed ideas in both old and newer areas.
  
 
==History==
 
==History==
 +
{{main|History of the bicycle}}
 +
[[Image:Draisine1817.jpg|200px|right|thumb|Drais' 1817 design made to measure]]
 +
[[Image:Ordinary bicycle01.jpg|thumb|left|A ''[[penny-farthing]]'' or ''ordinary bicycle'' photographed in the [[Škoda museum]] in the [[Czech Republic]].]]
 +
[[Image:BicyclePlymouth.jpg|thumb|left|Bicycle in Plymouth at the start of the twentieth century.]]
  
''Main article: [[History of the bicycle]]''
+
Through the centuries, several inventors and innovators contributed to the development of the bicycle. Its earliest known forebears were called ''[[velocipede]]s'', and included many types of human-powered vehicles. The first documented ancestor of the modern bicycle, first introduced to the public in Paris by the [[Germany|German]] [[Freiherr|Baron]] [[Karl Drais|Karl von Drais]] in 1818.<ref name="CSTM">{{cite web
 +
| title = Canada Science and Technology Museum: Baron von Drais’ Bicycle
 +
| year = 2006
 +
| url = http://www.sciencetech.technomuses.ca/english/collection/cycles2.cfm| accessdate = 2006-12-23
 +
}}</ref> These were known as ''pushbikes'', ''Draisines'' or "hobby horses." It was powered by the action of the rider's feet pushing against the ground. The Draisienne had two in-line wheels connected by a wooden frame. The rider sat astride and pushed it along with his feet, while steering the front wheel.
  
No single time or person can be identified with the invention of the bicycle. Its earliest known forebears were called ''[[velocipede]]s'', and included many types of human-powered vehicles.  One of these, the scooter-like ''[[dandy horse]]'', of the French Comte de Sivrac, dating to [[1790]], was long cited as the earliest bicycle. Most bicycle historians now believe that these hobby-horses with no steering mechanism probably never existed, but were instead made up by [[Louis Baudry de Saunier]], a 19th-century French bicycle historian.
+
[[Scotland|Scottish]] [[blacksmith]] [[Kirkpatrick MacMillan]] refined this in 1839 by adding a mechanical [[Crank (mechanism)|crank]] drive to the rear wheel, thus creating the first true "bicycle" in the modern sense. In the 1850s and 1860s, Frenchmen Ernest [[Michaux]] and [[Pierre Lallement]] took bicycle design in a different direction, placing the pedals on an enlarged front wheel. Their creation, which came to be called the "Boneshaker" or "penny-farthing" (more formally an ''[[penny-farthing|ordinary bicycle]]''), featured a heavy [[steel]] frame on which they mounted wooden wheels with [[iron]] tires. The primitive bicycles of this generation were difficult to ride, and the high seat and poor weight distribution made for dangerous falls.
[[Image:bicycle two 1886.jpg|thumb|280px|A smartly dressed couple seated on an 1886 "bicycle" for two.]]
 
The most likely originator of the bicycle is German [[Karl Drais|Baron Karl von Drais]], who rode his [[1816]] machine while collecting taxes from his tenants. He patented his ''draisine'', a number of which still exist, including one at the ''Paleis het Loo'' museum in [[Apeldoorn]], [[the Netherlands]]. These were ''pushbikes'', powered by the action of the rider's feet pushing against the ground.  Scottish blacksmith [[Kirkpatrick MacMillan]] shares creative credit with von Drais for adding a ''treadle'' drive mechanism, in [[1840]], that enabled the rider to lift his feet off the ground while driving the rear wheel. However, some reports describe MacMillan's vehicle as more of a "quadricycle".
 
  
In the [[1850s]] and [[1860s]], Frenchman Ernest Michaux and his pupil Pierre Lallement took bicycle design in a different direction, placing pedals on an enlarged front wheel.  Their creation, which came to be called the "Boneshaker", featured a heavy steel frame on which they mounted wooden wheels with iron tires. Lallement emigrated to America, where he recorded a patent on his bicycle in 1866. The Boneshaker was further refined by James Starley in the [[1870s]].  He mounted the seat more squarely over the pedals, so that the rider could push more firmly, and further enlarged the front wheel to increase the potential for speed. With tires of solid rubber, his machine became known as the ''ordinary''. British cyclists likened the disparity in size of the two wheels to their coinage, nicknaming it the ''[[penny-farthing]]''. The primitive bicycles of this generation were difficult to ride, and the high seat and poor weight distribution made for dangerous falls.
+
The subsequent ''dwarf ordinary'' addressed some of these faults by adding gearing, reducing the front wheel diameter, and setting the seat further back, with no loss of speed. Having to both pedal and steer via the front wheel remained a problem. Starley's nephew, [[John Kemp Starley|J. K. Starley]], J. H. Lawson, and Shergold solved this problem by introducing the [[chain drive]]. These models were known as ''dwarf safeties'', or ''safety bicycles'', for their lower seat height and better weight distribution. Starley's 1885 Rover is usually described as the first recognizably modern bicycle. Soon, the ''seat tube'' was added, creating the double-triangle, ''diamond frame'' of the modern bike.
+
 
The subsequent ''dwarf ordinary'' addressed some of these faults, by adding some kind of gearing, reducing the front wheel diameter and setting the seat further back with no loss of speed. However, having to both pedal and steer via the front wheel remained a problem. Starley's nephew, [[J. K. Starley]], J. H. Lawson, and Shergold solved this problem by introducing the ''chain'' and producing rear-wheel drive.   These models were known as ''dwarf safeties'', or ''safety bicycles'', for their lower seat height and better weight distribution. Starley's [[1885]] Rover is usually described as the first recognizably modern bicycle. Soon the ''seat tube'' was added, creating the double-triangle, ''diamond frame'' of the modern bike.
+
New innovations increased comfort, and ushered in the 1890s ''Golden Age of Bicycles''. In 1888, Scotsman [[John Boyd Dunlop]] introduced the [[pneumatic tire]], which soon became universal. Soon after, the rear [[freewheel]] was developed, enabling the rider to coast without the pedals spinning out of control. This refinement led to the 1898 invention of ''coaster brakes''. [[Derailleur gears]] and hand-operated, [[Bicycle brake systems|cable-pull brakes]] were also developed during these years, but were only slowly adopted by casual riders. By the turn of the century, bicycling clubs flourished on both sides of the Atlantic, and touring and racing were soon extremely popular.
''[[Image:BicyclePlymouth.jpg|left|thumb|Bicycle in Victorian Plymouth, with a predecessor of the Starley diamond-frame]]''
+
 
+
Bicycles and horse buggies were the two mainstays of private transportation just prior to the automobile, and the grading of smooth roads in the late 19th century was stimulated by the wide use of these devices.
While the Starley design was much safer, the return to smaller wheels made for a bumpy ride.  The next innovations increased comfort and ushered in the [[1890s]] ''Golden Age of Bicycles''. In [[1888]] Scotsman [[John Boyd Dunlop]] introduced the [[pneumatic tire]], which soon became universal. Shortly thereafter the rear [[freewheel]] was developed, enabling the rider to coast without the pedals spinning out of control. This refinement led to the [[1898]] invention of ''coaster brakes''. [[Derailleur gears]] and hand-operated, [[Bicycle brake systems|cable-pull brakes]] were also developed during these years, but were only slowly adopted by casual riders. By the turn of the century, bicycling clubs flourished on both sides of the Atlantic, and touring and racing were soon the rage.
 
  
Successful early bicycle manufacturers included Englishman [[Frank Bowden]] and German builder Ignaz Schwinn. Bowden started the [[Raleigh (bicycle)|Raleigh]] company in Nottingham in the 1890s, and soon was producing some 30,000 bicycles a year. Schwinn emigrated to the United States, where he founded his similarly successful company in Chicago in [[1895]]. [[Schwinn Bicycle Company|Schwinn]] bicycles soon featured widened tires and spring-cushioned, padded seats, sacrificing some efficiency for increased comfort.  Facilitated by connections between European nations and their overseas colonies, European-style bicycles were soon available worldwide. By the mid-[[20th century]] bicycles had become the primary means of transportation for millions of people around the globe.
+
==Technical aspects==
 +
[[Image:Bicycle.jpg|frame|Reflectors for night riding are among various safety accessories available.]]
  
[[image:Amsterdam-flowerbike.jpg|thumb|300px|A more-than-typical Amsterdam 'granny bike']]
+
===Legal requirements===
In many western countries the use of bicycles levelled off or declined, as motorized transportation became affordable and car-centered policies led to an increasingly hostile road environment for bicycles. In North America, bicycle sales declined markedly after [[1905]], to the point where by the [[1940]]s, they had largely been relegated to the role of children's toys.  In other parts of the world however, such as [[China]], [[India]], and European countries such as [[Germany]], [[Denmark]], and the [[Netherlands]], the traditional utility bicycle remained a mainstay of transportation, its design only gradually changing to incorporate hand-operated brakes and internal hub gears allowing up to seven speeds. In the Netherlands, old style bicycles so-called 'granny bikes', have remained very popular and are again being produced now the original supply is turning to rust. Especially [[Amsterdam]] granny bikes are often colourfully painted and/or otherwise decorated.
 
  
[[Image:Mountain bicycle.jpg|thumb|left|This ''[[Mountain bike|mountain bicycle]]'' features oversized tires, a sturdy frame, front shock absorbers, and handlebars oriented perpendicular to the bike's axis]]
+
The  1968 [[Vienna Convention on Road Traffic]] considers a bicycle to be a vehicle, and a person controlling a bicycle is considered a driver. The traffic codes of many countries reflect these definitions and demand that a bicycle satisfy certain legal requirements, sometimes even including licensing, before it can be used on public roads. In many jurisdictions it is an offence to use a bicycle that is not in roadworthy conditionIn most places, bicycles must have functioning front and rear [[bicycle lighting|lights]], or ''lamps'', when ridden after dark.  As some generator or dynamo-driven lamps only operate while moving, rear [[retroreflectors|reflectors]] are frequently also mandatory.  Since a moving bicycle makes very little noise, in many countries bicycles must have a warning bell for use when approaching pedestrians, equestrians and other bicyclists.
In North America, increasing consciousness of physical fitness and environmental preservation spawned a renaissance of bicycling in the late [[1960s]]. Bicycle sales in the United States boomed, largely in the form of the [[racing bicycle]]s long used in such events as the hugely popular [[Tour de France]]. Sales were also helped by a number of technical innovations that were new to the US market, including higher performance steel alloys and gearsets with an increasing number of gears. While 10-speeds were the rage in the 1970s, 12-speed designs were introduced in the 1980s, and today most bikes feature 18 or more speeds. By the 1980s these newer designs had driven the [[three-speed bicycle]] from the roads. In the late 1980s the [[mountain bike]] became particularly popular, and in the 1990s something of a major fad. These task-specific designs led many American recreational cyclists to demand a more comfortable and practical productManufacturers responded with the [[hybrid bicycle]], which restored many of the features long enjoyed by riders of the time-tested European [[utility bicycle|utility bikes]].
 
  
==Technical aspects==
+
===Standards===
[[Image:Bicycle.jpg|frame|Reflectors for night riding are one of many available safety accessories]]
+
A number of formal and industry standards exist for bicycle components, to help make spare parts exchangeable:
  
=== Legal requirements ===
+
* [[ISO 5775]] Bicycle tire and rim designations
The  1968 [[Vienna Convention on Road Traffic]] considers a bicycle to be a vehicle, and a person controlling a bicycle is considered a driver.  The traffic codes of many countries reflect these definitions and demand that a bicycle satisfy certain legal requirements, including licencing, before it can be used on public roads.  In many jurisdictions it is an offence to use a bicycle that is not in roadworthy condition and which does not have functioning front and rear [[bicycle brake systems|brakes]].  In some places, bicycles must have functioning front and rear [[bicycle lighting|lights]] or ''lamps''.  As some generator or dynamo-driven lamps only operate while moving, rear [[retroreflectors|reflectors]] are frequently also mandatory.  Since a moving bicycle makes very little noise, in many countries bicycles must have a warning bell for use when approaching pedestrians, equestrians and other bicyclists.
+
* ISO 8090 Cycles &mdash; Terminology (same as BS 6102-4)
 +
* ISO 4210 Cycles &mdash; Safety requirements for bicycles
  
 
===Construction and parts===
 
===Construction and parts===
 
 
====Frame====
 
====Frame====
 +
{{main|Bicycle frame}}
  
:''Main article: [[Bicycle frame]]''
+
Nearly all modern [[upright bicycle]]s feature the ''diamond frame'', a [[truss]], consisting of two [[triangle]]s: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube and seat tube. The head tube contains the [[headset (bicycle part)|headset]], the set of bearings that allows the [[bicycle fork|fork]] to turn smoothly for steering and balance. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the [[bottom bracket]]. The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the [[bicycle chain|chain]], connecting the bottom bracket to the rear [[Dropout (bicycle part)|dropouts]]. The seat stays connect the top of the seat tube at or near the same point as the top tube) to the rear dropouts.
 
+
[[Image:Bikeinindia.JPG|left|thumb|250px|Bike on the beach in Goa, India]]
Nearly all modern [[upright bicycle]]s feature the ''diamond frame'', composed of two [[triangle]]s: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube and seat tube. The head tube contains the [[headset (bicycle part)|headset]], the interface with the [[bicycle fork|fork]]. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the [[bottom bracket]]. The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the [[bicycle chain|chain]], connecting the bottom bracket to the rear dropouts. The seat stays connect the top of the seat tube (often at or near the same point as the top tube) to the rear dropouts.
 
  
Historically, women's bicycle frames had a top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height. This allowed the rider to dismount while wearing a skirt or dress. Although some women's bicycles continue to use this frame style, there is also a hybrid form, the ''mixte'' or ''step-through frame'', which also allows easier mounting and dismounting for both male and female riders.
+
Historically, women's bicycle frames had a top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height at the expense of compromised structural integrity, since this places a strong bending load in the seat tube, and bicycle frame members are typically weak in bending. This design purportedly allows the rider to mount and dismount in a dignified way while wearing a skirt or dress, an action made difficult by a properly-sized diamond frame. While some women's bicycles continue to use this frame style, there is also a hybrid form, the ''mixte'' or ''[[step-through frame]]'', which splits the top tube into two small top tubes that bypass the seat tube and connect to the rear dropouts. The ease of stepping through is also appreciated by those with limited flexibility or other joint problems. Unfortunately for the old tall man, because of its persistent image as a "women's" bicycle, the vast majority of mixte frames are quite small.
  
Historically, materials used in bicycles have followed a similar pattern as in aircraft, the goal being strength and low weight.  Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. [[Celluloid]] found application in mudguards, and aluminum alloys are increasingly used in components such as handlebars, seat stems (also known as seatposts), and brake levers. In the [[1980s]] [[aluminum]] alloy frames became popular, and their affordability now makes them common.  More expensive [[carbon fibre]] and [[titanium]] frames are now also available, as well as advanced steel alloys.
+
Historically, materials used in bicycles have followed a similar pattern as in aircraft, the goal being strength and low weight.  Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. [[Celluloid]] found application in mudguards, and aluminium alloys are increasingly used in components such as handlebars, seat post, and brake levers. In the 1980s [[aluminium]] alloy frames became popular, and their affordability now makes them common.  More expensive [[carbon fiber]] and [[titanium]] frames are now also available, as well as advanced steel alloys.
  
 
====Drivetrain====
 
====Drivetrain====
 +
{{details|bicycle gearing}}
 +
[[Image:Shimano xt rear derailleur.jpg|right|thumb|Shimano XT rear derailleur on a mountain bike]]
  
The ''drivetrain'' begins with [[bicycle pedal|pedals]] which rotate the [[crankset]], which fit into the [[bottom bracket]]. Attached to the crank is the ''chainring'' which drives the [[bicycle chain|chain]], which in turn rotates the rear wheel via the rear [[sprocket]]s. Between the chain and rear wheel may be interspersed various gearing systems, described below, which vary the [[gear ratio]], the number of rear wheel revolutions produced by each turn of the pedals.   
+
The ''drivetrain'' begins with [[bicycle pedal|pedals]] which rotate the [[Crank set|cranks]], which connect to the [[bottom bracket]]. Attached to the (usually right) crank arm may be one or more ''chainring''s or sprockets which drive the [[bicycle chain|chain]], which in turn rotates the rear wheel via the rear [[sprocket]]s ([[cassette (bicycle part)|cassette]] or freewheel). Various [[bicycle gearing|gearing systems]] may be interspersed between the pedals and rear wheel; these gearing systems vary the number of rear wheel revolutions produced by each turn of the pedals.   
  
Since cyclists' legs produce a limited amount of power most efficiently over a narrow range of ''[[Cadence (cycling)|cadences]]'', a variable gear ratio is needed to maintain an optimum pedaling speed while covering varied terrain.  The gear systems are hand-operated, via cables (or rarely, hydraulics), and are of two types.
+
Since cyclists' legs produce a limited amount of power most efficiently over a narrow range of ''[[Cadence (cycling)|cadences]]'', a variable [[gear ratio]] is helpful to maintain an optimum pedalling speed while covering varied terrain.
* ''Internal [[hub gear]]ing'' works by [[Epicyclic gearing|planetary, or epicyclic, gearing]], in which the outer case of the hub gear unit turns at a different speed relative to the rear axle depending on which gear is selected.  Rear hub gears may offer 3, 4, 5, 6, 7, 8, 12, or 14 speeds.  Bottom bracket fittings offer a choice of 2 speeds. 
 
*  ''External gearing'' utilizes [[derailleur gear|derailleurs]], which can be placed on both the front ''chainring'' and on the rear ''cluster'' or ''cassette'', to push the chain to either side, derailing it from the sprockets. The sides of the gear rings catch the chain, pulling it up onto their teeth to change gears.  There may be 1 to 3 chainrings, and 5 to 10 sprockets on the cassette.
 
 
 
Internal hub gears are much less affected by adverse weather conditions than derailleurs, and often last longer and require less maintenance.  However, they may be heavier and/or more expensive, and often do not offer the same range or number of gears.
 
Internal hub gearing still predominates in some regions, particularly on utility bikes, whereas in other regions, such as the USA, external derailleur systems predominate.
 
  
 +
The fundamental working/application of a rear gear is explained as follows. When the bicycle chain is linked to a freewheel with higher radius (the lower gear) every cycle on the pedal leads to fewer rotations in the freewheel (and hence the rear wheel). This results in covering lesser distance for each pedal cycle. The primary source of tiredness in bicycling is the power that the rider dissipates and not the energy (for instance, a person covering a mile at 1 mile per hour will get less tired than a person covering a mile at 10 miles an hour, even though both spend the same energy). Thus power lost indicates the effort spent. In an upslope, the energy needed to cover a distance is greater than that needed on a flat surface for the same distance. Thus to maintain the same effort (or power lost) even while riding on an upslope, a rider should shift to a lower gear with the pedalling speed maintained at the same level as that on a flat surface. This adjustment increases the time taken to cover the considered distance. Thus more time is spent in dissipating the higher energy needed in an upslope. This helps to maintain a power (or effort) same as that of a flat surface. The dual of this strategy where the rider shifts to a higher gear can be used to increase the speed of travel at the cost of increased power dissipation. Gears, hence, give the rider a provision to choose a desired speed at the cost of effort and vice versa.
 +
 
Road bicycles have ''close set'' multi-step gearing, which allows very fine control of cadence, while ''utility cycles'' offer fewer, more widely spaced speeds. ''Mountain bikes'' and most entry-level road racing bikes may offer an extremely low gear to facilitate climbing slowly on steep hills.
 
Road bicycles have ''close set'' multi-step gearing, which allows very fine control of cadence, while ''utility cycles'' offer fewer, more widely spaced speeds. ''Mountain bikes'' and most entry-level road racing bikes may offer an extremely low gear to facilitate climbing slowly on steep hills.
  
Fixed-gear track racing bikes have transmission efficiencies of over 99% (nearly all the energy put in at the pedals ends up at the wheel). Whilst variable ratio gear mechanisms are essential for human efficiency, they do reduce mechanical efficiency. The efficiency varies considerably with the gear ratio being used. In a typical hub gear mechanism the mechanical efficiency will be between 82% and 92% depending on the ratio selected. Which ratios are ''best'' and ''worst'' depends on the specific model of hub gear. Derailleur type mechanisms fare better, with a typical mid-range product (of the sort used by serious amateurs) achieving between 88% and 99% efficiency at 100W. In derailleur mechanisms the highest efficiency is achieved by the larger cogs and, generally speaking, efficiency decreases with smaller cog sizes. This is because the chain must bend more sharply as it rolls on and off the cog, and also forms a sharp angle at the chain tensioner<sup>[[#Notes|9]]</sup>. Efficiency is also compromised on derailleur drivetrains if the chain is running large-ring to large-cog or small-ring to small-cog; this is called '''cross-chaining''', and also results in increased wear because of the lateral deflection of the chain. [[Retro-Direct]] was a type of drivetrain used on some bicycles in the early [[20th century]] that has been resurrected by bicycle hobbyists.
+
====Steering and seating====
  
====Steering and seating====
+
The [[handlebar]]s turn the [[bicycle fork|fork]] and the front [[bicycle wheel|wheel]] via the ''stem'', which articulates with the [[headset (bicycle part)|headset]].  Three styles of handlebar are common.  ''Upright handlebars'', the norm in Europe and elsewhere until the 1970s, curve gently back toward the rider, offering a natural grip and comfortable upright position.  ''Drop handlebars'' are "dropped," offering the cyclist either an aerodynamic "crouched" position or a more upright posture in which the hands grip the brake lever mounts.  Mountain bikes feature a ''straight handlebar'', which helps prevent the rider from pitching over the front in case of sudden deceleration.
  
The [[handlebar]]s rotate the [[bicycle fork|fork]] and the front [[bicycle wheel|wheel]] via the ''stem'', which articulates with the [[headset (bicycle part)|headset]]. Three styles of handlebar are common.  ''Touring handlebars'', the norm in Europe and elsewhere until the [[1970s]], curve gently back toward the rider, offering a natural grip and comfortable upright position. ''Racing handlebars'' are "dropped", offering the cyclist either an aerodynamic "hunched" position or a more upright posture in which the hands grip the brake lever mounts.  Mountain bikes feature a crosswise handlebar, which helps prevent the rider from pitching over the front in case of sudden deceleration.
+
Variations on these styles exist. ''Bullhorn'' style handlebars are often seen on modern [[time trial bicycle]]s, equipped with two forward-facing extensions, allowing a rider to rest the entire forearm on the bar. These are usually used in conjunction with the ''aero bar'', a pair of forward-facing extensions spaced close together, to promote better aerodynamics. The ''Bullhorn'' was banned from ordinary road racing because it is difficult for the rider to control in bike traffic.
  
Variations on these styles exist. The ''Bullhorn'' style handlebars are often seen on modern Time Trial specific bicycles, equipped with two forward-facing extensions, allowing a rider to rest his entire forearm on the bar. These are usually used in conjunction with the ''aero bar'', a pair of forward-facing extensions spaced close together, to allow the rider a position of increased aerodynamics. The ''Bullhorn'' style handlebars are banned from ordinary road racing because it is considered there is less fine control in bike traffic.
+
''Saddles'' also vary with rider preference, from the cushioned ones favoured by short-distance riders to narrower saddles which allow more free leg swings. Comfort depends on riding position.  With comfort bikes and hybrids the cyclist sits high over the seat, their weight directed down onto the saddle, such that a wider and more cushioned saddle is preferable. For racing bikes where the rider is bent over, weight is more evenly distributed between the handlebars and saddle, and the hips are flexed, and a narrower and harder saddle is more efficient.  
 
''Seats'', or ''saddles'', also vary depending on rider preference, from the cushioned ones favoured by short-distance riders to narrower seats which allow more free leg swings. Comfort depends on riding position.  With comfort bikes and hybrids the cyclist sits high over the seat, their weight directed down onto the saddle, such that a wider and more cushioned saddle is preferable. For racing bikes where the rider is bent over, weight is more evenly distributed between the handlebars and saddle, and the hips are flexed. For this style of riding a narrower and harder saddle is more efficient.  
 
  
[[Recumbent bicycle]]s have more chair-like seats, and so are much more comfortable to ride, although generally slower up hills due to this positioning.  The reclined, low seating position does provide increased aerodynamics over standard seating.
+
A [[recumbent bicycle]] has a reclined chair-like seat that is more comfortable than a saddle, especially for riders who suffer from certain types of back pain.
  
 
====Brakes====
 
====Brakes====
 +
{{main|bicycle brake systems}}
 +
[[Image:Pedderson-bremse.jpg|thumb|Semi low-profile cantilever brake]]
  
:''Main article: [[Bicycle brake systems]]''
+
Modern bicycle ''brakes'' are either ''rim brakes'', in which friction pads are compressed against the wheel rims, ''internal hub brakes'', in which the friction pads are contained within the wheel hubs, or ''disc brakes''. A rear hub brake may be either hand-operated or pedal-actuated, as in the back pedal ''coaster brakes'' which were the rule in North America until the 1960s, and are still common in children's bicycles. Hub drum brakes do not cope well with extended braking, so rim or disc brakes are favored in hilly terrain. With hand-operated brakes, force is applied to brake handles mounted on the handle bars and then transmitted via [[Bowden cable]]s or hydraulic lines to the friction pads. [[Disc brakes]] appeared in the late 1990s on some off-road bicycles, [[tandem bicycle|tandem]]s and [[recumbent bicycle]]s, but are considered impractical on road bicycles, which rarely encounter conditions where the advantages of discs are significant.
  
Bicycle ''brakes'' are either ''rim brakes'', in which friction pads are compressed against the wheel rims, ''internal hub brakes'', in which the friction pads are contained within the wheel hubs, or disc brakes. A rear hub brake may be either hand-operated or pedal-actuated, as in the back pedal ''coaster brakes'' which were the rule in North America until the [[1960]]sHub drum brakes do not cope well with extended braking, so rim brakes are favoured in hilly terrain.  With hand-operated brakes, force is applied to brake handles mounted on the handle bars and then transmitted via [[Bowden cable]]s to the friction pads.  In the late [[1990s]], [[disc brakes]] appeared on some off-road bicycles, [[tandem bicycle|tandem]]s and [[recumbent bicycle]]s, but are considered impractical on road bicycles, which rarely encounter conditions where the advantages of discs are significant.
+
For [[track cycling]], [[track bicycle]]s do not have brakes. Brakes are not required for riding on a track because all riders ride in the same direction and there are no corners or other traffic. Track riders are still able to slow down because all track bicycles are [[Fixed-gear bicycle|fixed-gear]], meaning that there is no freewheelWithout a freewheel, coasting is impossible, so when the rear wheel is moving, the crank is moving. To slow down one may apply resistance to the pedals. Cyclists who ride a track bike without brake(s) on the road can also slow down by skidding, by unweighting the rear wheel and applying  a backwards force to the pedals, causing the rear wheel to lock up and slide along the road. Most track bike frames and forks do not have holes for mounting brakes, although with their increasing popularity among some road cyclists, some manufacturers have designed their track frames to enable the fitting of brakes.
  
The advantages of discs make them well-suited to steep, extended downhills through wet and muddy off-road terrain, which falls under the category of downhill and freeride bicycle riding.  The use of tires as large as 3.0 inches in width also makes disc brakes a necessity, as rim brakes simply cannot straddle a tire that wide.
+
====Suspension====
 +
{{main|bicycle suspension}}
  
Two main disc brake systems exist: hydraulic and mechanical (cable-actuated).  Mechanical disc brakes have less modulation than hydraulic disc brake systems, and since the cable is usually open to the outside, mechanical disc brakes tend to pick up small bits of dirt and grit in the cable lines when ridden in harsh terrain. Hydraulic disc brake systems generally keep contaminants out better.  However, since hydraulic disc brakes usually require relatively specialized tools to bleed the brake systems, repairs on the trail are difficult to perform, whereas mechanical disc brakes rarely fail.  Also, the hydraulic fluid may boil on steep, continuous downhills.  This is due to the brake losing its ability to transmit force through incompressible fluids, since some of it has become a gas, which is compressible.  For these reasons, one must weigh the advantages and disadvantages of using a hydraulic system versus a mechanical system.
+
Bicycle suspension refers to the system or systems used to ''suspend'' the rider and all or part of the bicycle in order to protect them from the roughness of the terrain over which they travel. Bicycle suspension are used primarily on [[mountain bicycle]]s, but are also common on [[hybrid bicycle]]s, and can even be found on some [[road bicycle]]s.
  
 
====Accessories and repairs====
 
====Accessories and repairs====
 +
Some components, which are often optional accessories on sports bicycles, are standard features on [[utility bicycles]] to enhance their usefulness and comfort.  [[Chainguard]]s and [[mudguard]]s, or ''fenders'', protect clothes and moving parts from oil and spray.  [[Kick stand]]s help with parking.  Front-mounted wicker or steel ''baskets'' for carrying goods are often used.  [[Bicycle rack#Bicycle mounted bike racks|Rear racks]] or carriers can be used to carry items such as school satchels.  Parents sometimes add rear-mounted child seats and/or an auxiliary saddle fitted to the crossbar to transport children.
 +
[[Image:Reiserad-beladen.jpg|right|thumb|Touring bicycle equipped with head lamp, pump, rear rack, fenders/mud-guards, and numerous saddle-bags.]]
  
Utility bicycles have many standard features which enhance their usefulness and comfort that would be considered accessories on sports bicycles.  ''Chainguards'' and ''mudguards'', or ''fenders'', protect clothes and moving parts from oil and spray.  ''Kick stands'' help with parking.  Front-mounted wicker or steel ''baskets'' for carrying goods are often used.  Rear racks or carriers can be used to carry items such as school satchels.  Parents sometimes add rear-mounted child seats and/or an auxiliary saddle fitted to the crossbar to transport children.
+
''Toe-clips and toestraps'', or clipless pedals, help to keep the foot planted firmly on the pedals, and enable the cyclist to pull as well as push the pedals. Technical accessories include solid-state speedometers and odometers for measuring distance. Other accessories include [[bicycle lighting|lights]], reflectors, tire pump, security lock, mirror, and horn.<ref name="bicycleuniverse"> {{cite web|url=http://bicycleuniverse.info/eqp/accessories.html#safety |title=Safety Accessories |accessdate=2006-09-13 |last=Bluejay |first=Michael |work=Bicycle Accessories |publisher=BicycleUniverse.info}} </ref> A [[bicycle helmet]] is classified by some as an accessory,<ref name="bicycleuniverse" /> but as an item of clothing by others.<ref> {{cite web|url=http://bicycling.about.com/library/weekly/aa041098.htm |title=The Essentials of Bike Clothing |accessdate=2006-09-13 |work=About Bicycling |publisher=About.com}} </ref>
[[Image:Reiserad-beladen.jpg|left|thumb|Touring bicycle equipped with head lamp, pump, rear rack, fenders/mud-guards, and numerous saddle-bags.]]
 
Other accessories include lights, pump, lock, and additional (pedal or wheel-mounted) reflectors. Technical accessories include solid-state speedometers and odometers for measuring distance. ''Toe-clips'' help to keep the foot planted firmly on the pedals, and enable the cyclist to pull as well as push the pedals.
 
  
In North America, a large minority, possibly up to 25% in the US, of bicyclists wear plastic [[bicycle helmet]]s for safety. There is no US federal law requiring the use of helmets, but the majority of states require children up to a certain age to wear them; a number of cities and counties in [[Washington]] require them for riders of all ages. In most European countries, helmets are viewed as an indicator of inexperience or recklessness, and their use is considered unusual for adult utility cyclists.  In [[Australia]] and [[New Zealand]], and parts of [[Canada]], such helmets are required by law. The use of helmets by utility cyclists is practically unknown in most other regions.
+
Many cyclists carry ''tool kits'', containing at least a tire patch kit (and/or a spare tube), [[tire lever]]s, and hex wrenches.  A single tool once sufficed for most repairs. More specialised parts now require more complex tools, including proprietary tools specific for a given manufacturer.   Some bicycle parts, particularly hub-based gearing systems, are complex, and many prefer to leave [[repair and maintenance|maintenance and repairs]] to professional [[bicycle mechanic]]s.  Others maintain their own bicycles, enhancing their enjoyment of the [[hobby]] of cycling.
  
Many cyclists also carry ''tool kits'', containing at least a patch kit for tires, [[tire lever]]s,  and some spanners. At one time it was possible to use a single tool to carry out most common bicycle repairs.  More specialised parts now often require more complex tools, including proprietary tools specific for a given manufacturer.  Some bicycle parts, particularly hub-based gearing systems, are complex, and many people prefer to leave most [[repair and maintenance|maintenance and repairs]] to professionals.  Others maintain their own bicycles, finding it enhances their enjoyment of the [[hobby]] of cycling.
+
It is also possible to purchase road-side assistance from companies such as the [[Better World Club]].
  
 
===Performance===
 
===Performance===
 +
{{main|bicycle performance}}
  
In both biological and mechanical terms, the bicycle is extraordinarily efficient. In terms of the amount of energy a person must expend to travel a given distance, investigators have calculated it to be the most efficient self-powered means of transportation.<sup>[[#Notes|1]]</sup> From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels, although the use of gearing mechanisms may reduce this by 10-15% <sup>[[#Notes|2]]</sup> <sup>[[#Notes|9]]</sup>. In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also a most efficient means of cargo transportation.
+
In both biological and mechanical terms, the bicycle is extraordinarily efficient. In terms of the amount of energy a person must expend to travel a given distance, investigators have calculated it to be the most efficient self-powered means of transportation.<ref>"Bicycle Technology," S.S. Wilson, [[Scientific American]], March 1973</ref> From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels, although the use of gearing mechanisms may reduce this by 10-15%.<ref>
 +
[http://www.jhu.edu/~gazette/1999/aug3099/30pedal.html "Johns Hopkins Gazette"],
 +
30 August 1999</ref><ref name="whitt">{{cite book
 +
| title = Bicycling Science
 +
| edition = Second edition
 +
| last = Whitt
 +
| first = Frank R.
 +
| coauthors = David G. Wilson
 +
| year = 1982
 +
| publisher = Massachusetts Institute of Technology
 +
| id = ISBN 0-262-23111-5
 +
| pages = 277-300}}</ref>
 +
In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also a most efficient means of cargo transportation.
  
[[Image:RacingBicycle-non.JPG|right|thumb|Racing bicycles have dropped handlebars, a narrow seat, and minimal accessories.]]
+
A human being travelling on a bicycle at low to medium speeds of around 10-15 mph (16-24 km/h), using only the energy required to walk, is the most energy-efficient means of transport generally available. Air drag, which increases with the square of speed, requires dramatically higher power outputs with increasing speed. A bicycle which places the rider in a seated position, [[supine position]] or, more rarely, [[prone position]], and which may be covered in an aerodynamic fairing to achieve very low air drag, is referred to as a [[recumbent bicycle]] or [[human powered vehicle]].  Humans create the greatest amount of drag on an upright bicycle at about 75% of the total drag.
  
On firm, flat, ground, a 70 kg man requires about 100 watts to walk at 5 km/h. That same man on a bicycle, on the same ground, with the same power output, can average 25 km/h, so energy expenditure in terms of kcal/kg/km is roughly one-fifth as much. Generally used figures are
+
===Dynamics===
* 1.62 kJ/(km∙kg) or 0.28 kcal/(mile∙lb) for cycling,
+
{{main|Bicycle and motorcycle dynamics}}
* 3.78 kJ/(km∙kg) or 0.653 kcal/(mile∙lb) for walking/running,
 
* 16.96 kJ/(km∙kg) or 2.93 kcal/(mile∙lb) for swimming.
 
  
For many people whose running might be limited by muscle and knee pain, cycling offers comparable outdoor exercise that can be enjoyed by people of a wide range of fitness levels: it is a "no-impact" sport that is easy on the body as long as the bike is properly "fit."  In addition, since bicycling can also provide convenient transportation, less self-discipline may be required to keep to the activity, since it has a  practical purpose. However, because of its efficiency, cycling requires a longer distance, and often greater time, than running to consume the same amount of energy.
+
A bicycle stays upright by being steered so as to keep its centre of gravity over its wheels. This steering is usually provided by the rider, but under certain conditions may be provided by the bicycle itself.
  
The average "in-shape" man can produce about 3 watts/kg for more than an hour (e.g., around 200 watts for a 70 kg rider), with top amateurs producing 5 watts/kg and elite athletes achieving 6 watts/kg for similar lengths of time. Elite track sprinters are able to attain an instantaneous maximum output of around 2,000 watts, or in excess of 25 watts/kg; elite road cyclists may produce 1,600 to 1,700 watts as an instantaneous maximum in their burst to the finish line at the end of a five-hour long road race. Even at moderate speeds, most cycling energy is spent in overcoming aerodynamic [[drag (physics)|drag]], which increases with the square of speed; therefore, power needs increase approximately with the cube of speed.
+
A bicycle must lean in order to turn. This lean is induced by a method known as [[countersteering]], which can be performed by the rider turning the handlebars directly with the hands or indirectly by leaning the bicycle.
 
Typical speeds for bicycles are 16 to 32&nbsp;[[km/h]] (10 to 20&nbsp;[[mph]]). On a fast racing bicycle, a reasonably fit rider can ride at 50&nbsp;km/h (30&nbsp;mph) on flat ground for short periods. The highest speed ever officially attained on the flat, without using motor pacing and wind-blocks, is by Canadian [[Sam Whittingham]], who in [[2002]] set a 130.36&nbsp;km/h (81.00&nbsp;mph) record on his highly aerodynamic [[recumbent bicycle]]. This stands as the official record for all human-powered vehicles.
 
  
There has been major corporate competition to lower the weight of racing bikes through the use of advanced materials and components. Additionally, advanced wheels are available with low-friction bearings and other features to lower road resistance. In measured tests these components have almost no effect on cycling performance. For instance, lowering a bike's weight by 1 kg, a major effort considering they may weigh less than 15 kg to start with, will have the same effect over a 40 km [[time trial]] as removing a protrusion into the air the size of a pencil. For this reason more recent designs have concentrated on lowering wind resistance, using aerodynamically shaped tubing, flat spokes on the wheels, and handlebars that allow the rider to bend over into the wind. These changes can impact performance dramatically, cutting minutes off a time trial.
+
Short-wheelbase or [[tall bike|tall bicycles]], when braking, can generate enough stopping force at the front wheel in order to flip longitudinally. This action, especially if performed on purpose, is known as a [[stoppie]] or front wheelie.
  
===Bicycle physics===
+
===Further reading===
A rider stays upright on a bicycle by steering the bicycle so that the point where the wheels touch the ground stays underneath the center of gravity. Once underway, this effort is largely replaced by physical forces generated by the rotation of the wheels which produce a remarkable "self-steering" effect.<sup>[[#Notes|3]]</sup> The [[angular momentum]] of the wheels and the [[torque]] applied to them by the ground generates a phenomenon called [[precession]], by which the wheel turns, or ''trails'', toward whichever side the bicycle tilts. Like the rider's steering adjustments, this motion automatically returns the contact point of the wheel directly under the center of gravity.  These forces, perhaps aided at very high speeds by the gyroscopic effect of the spinning wheels,<sup>[[#Notes|4]]</sup> are sufficiently strong that a riderless bicycle going down a slope will stay upright by itself.  Conversely, a bicycle whose steering fork is ''locked'' in a perfectly straight ahead position is virtually impossible to balance.
 
 
 
That gyroscopic effects are unimportant at normal cycling speeds was shown by physicist and researcher into bicycle stability [[David E. H. Jones]], whose series of "URBs" ("unrideable bikes" with various modifications to the front end) included a bike which cancelled the gyroscopic effect of the front wheel by dint of attaching a second wheel to his front forks (alongside the regular wheel) whose lower edge was about an inch (25 mm) above the ground.  By gearing this wheel to the regular front wheel so that it spun in the opposite direction at equal speed, the net angular momentum of both wheels together was close to zero.  Jones found he could ride this bike with no difficulty, but did discover that without a rider the non-gyroscopic bike fell over much faster than a regular bike.
 
 
 
Stability is also influenced by a geometric factor called ''trail''. This is the distance between the point of contact the front wheel makes with the ground and the place the steering axis makes contact with the ground. The greater the amount of trail, the greater the reaction. One can see the effect that trail has by simply holding a bicycle by the seat and leaning it. The moment due to trail and the weight of the bicycle will turn the front wheel in the direction of the turn. Negative trail (rolling a bicycle backwards) results in immediate steering problems. Zero trail (as in a unicycle) requires constant rider adjustment. Positive trail - found on typical bicycles - creates positive stability by steering the contact patch back under the CG of the bicycle and rider. [http://www.johnforester.com/Articles/BicycleEng/dahon.htm] [http://www.velonews.com/tech/report/articles/7322.0.html]
 
 
 
At higher speeds bicycles can also experience [[speed wobble|speed wobbles]] or shimmies, where the front wheel spontaneously oscillates to the left and right.  While the wobbles can be easily remedied by slowing down, adjusting position, or relaxing one's grip on the handlebars, speed wobbles can be [http://www.mailtribune.com/archive/2004/0915/local/stories/01local.htm fatal]
 
 
 
This shimmy is often seen in shopping cart front wheels. Some otherwise minor irregularity accelerates the wheel to one side. The restoring force is applied in phase with the progress of the irregularity, and the wheel turns to the other side where the process is repeated. If there is insufficient damping in the steering the oscillation will increase until system failure. Speed changes, making the bicycle/motorcycle stiffer or lighter, or increasing the stiffness of the steering (of which the rider is the main component) can change the oscillation frequency, though only speed change is applicable in the situation.
 
  
 
For more information on the technical aspects of bicycles, see also:
 
For more information on the technical aspects of bicycles, see also:
Line 129: Line 146:
 
<!-- *[[Bicycle brake systems]] —>
 
<!-- *[[Bicycle brake systems]] —>
 
<!-- *[[Bicycle lighting]] —>
 
<!-- *[[Bicycle lighting]] —>
 +
<!-- *[[Bicycle physics]] —>
  
 
==Social and historical aspects==
 
==Social and historical aspects==
[[Image:BikesInAmsterdam 2004 SeanMcClean.jpg|right|thumb|Present day: Bikes still popular in Amsterdam]]
+
[[Image:BikesInAmsterdam 2004 SeanMcClean.jpg|right|thumb|Present day: Bikes are popular in Amsterdam]]
 
 
===Economic and social implications===
 
  
Bicycle manufacturing proved to be a training ground for other industries.  Building modern bicycle frames led to the development of advanced metalworking techniques, both for the frames themselves and for special components such as [[Bearing (mechanical)|ball bearings]], [[washer (mechanical)|washer]]s, and [[sprocket]]s. These techniques later enabled skilled metalworkers and mechanics to develop the components used in early [[automobile]]s and [[aircraft]]. J. K. Starley's company became the ''Rover Cycle Company Ltd.'' in the late 1890s, and then the ''[[Rover (car)|Rover]]'' auto maker.  The [[Morris Motor Company]] and [[Škoda Auto|Škoda]] also began in the bicycle business, as did [[Henry Ford]] and the [[Wright Brothers]].
+
===Economic implications===
 +
Bicycle manufacturing proved to be a training ground for other industries and led to the development of advanced metalworking techniques, both for the frames themselves and for special components such as [[Bearing (mechanical)|ball bearings]], [[washer (mechanical)|washer]]s, and [[sprocket]]s. These techniques later enabled skilled metalworkers and mechanics to develop the components used in early [[automobile]]s and [[aircraft]]s. J. K. Starley's company became the Rover Cycle Company Ltd. in the late 1890s, and then the [[Rover (car)|Rover]] auto maker.  The [[Morris Motor Company]] (in [[Oxford]]) and [[Škoda Auto|Škoda]] also began in the bicycle business, as did the [[Wright Brothers]].<ref>
 +
{{cite web
 +
| title = The Wrights' bicycle shop
 +
| year = 2007
 +
| url = http://www.nasm.si.edu/Wrightbrothers/who/1893/shop.cfm
 +
| accessdate = 2007-02-05
 +
}}</ref>
  
Some of the bicycle clubs and national associations became prominent advocates for improvements to roads and highways. In the [[United States]], the [[League of American Wheelmen]] was a prominent advocate for the improvement of roads in the last part of the 19th century, founding and leading the national [[Good Roads Movement]] in the US.
+
In general, U.S. and European cycle manufacturers used to assemble cycles from their own frames and components made by other companies, although very large companies (such as Raleigh) used to make almost every part of a bicycle (including bottom brackets, axles, etc.) In recent years, those bicycle makers have greatly changed their methods of production. Now, almost none of them produce their own frames. Many newer or smaller companies only design and market their products; the actual production is done by eastern companies. For example, some sixty percent of the world's bicycles are now being made in China. Despite this shift in production, as nations such as [[China]] and [[India]] become more wealthy, their own use of bicycles has declined due to the increasing affordability of cars and motorcycles. One of the major reasons for the proliferation of Chinese-made bicycles in foreign markets is the lower cost of labour in China.<ref>[[The Economist]], 15 February 2003</ref>
  
[[Image:WhiteBikesVeluwe.jpg|thumb|250px|left|In the Netherlands, bicycles are made available for use in national parks]]The evolution of the bicycle had less tangible effects as well, extending early to areas as diverse as fashion and politics.  In the [[1890s]] the cycling craze led to a new set of fashions, including ''bloomers'', which helped liberate women from corsets and other restrictive clothing.  A British perfumer marketed ''Cycling Bouquet'', which came in a tiny vial designed to fit into a lady cyclist's purse. The diamond-frame safety bicycle gave women unprecedented mobility, contributing to their emancipation in Western nations.  Sociologists suggest that bicycles enlarged the gene pool for rural workers, by enabling them to easily reach the next town and increase their ''courting radius''.  In cities, bicycles helped reduce crowding in inner-city tenements by allowing workers to commute from single-family dwellings in the suburbs. They also reduced dependence on horses, and allowed people to travel into the country, since bicycles were three times as energy efficient as walking, and three to four times as fast.  In North America, the political organization of bicycle enthusiasts, in such groups as the ''League of American Wheelmen'', led to further changes.  Both their model for political organization and the paved roads for which they argued facilitated the growth of the bicycle's rival, the [[automobile]].
+
===Female emancipation===
  
In recent years, US and European bicycle makers have moved much of their production to Asia. Some sixty percent of the world's bicycles are now being made in China. Despite this shift in production, as nations such as China and India become more wealthy, their own use of bicycles has declined. One of the major reasons for the proliferation of Chinese-made bicycles in foreign markets is the increasing affordability of cars and motorcycles for its own citizens <sup>[[#Notes|5]]</sup>.
+
[[Image:Woman with Bicycle 1890s.jpg|thumb|Woman with bicycle, 1890s]]
 +
The diamond-frame safety bicycle gave women unprecedented mobility, contributing to [[Emancipation of women|their emancipation]] in Western nations. As bicycles became safer and cheaper, more women had access to the personal freedom they embodied, and so the bicycle came to symbolise the [[New Woman]] of the late nineteenth century, especially in Britain and the United States.
  
===Bicycles at work===
+
The bicycle was recognised by nineteenth-century [[feminist]]s and [[suffragist]]s as a "freedom machine" for women.  American [[Susan B. Anthony]] said in a ''[[New York World]]'' interview on February 2 1896: "Let me tell you what I think of bicycling. I think it has done more to emancipate women than anything else in the world. It gives women a feeling of freedom and self-reliance. I stand and rejoice every time I see a woman ride by on a wheel...the picture of free, untrammelled womanhood." In 1895 [[Frances Willard]], the tightly-laced president of the [[Women’s Christian Temperance Union]], wrote a book called ''How I Learned to Ride the Bicycle'', in which she praised the bicycle she learned to ride late in life, and which she named "Gladys," for its "gladdening effect" on her health and political optimism.  Willard used a cycling metaphor to urge other suffragists to action, proclaiming, "I would not waste my life in friction when it could be turned into momentum."
[[Image:PoliceOfficerOnBike.jpg|thumb|right|Police officer on a bicycle]]
 
  
The [[mail|postal service]]s of many countries have long relied on bicycles.  The [[Royal Mail]] first started using bicycles in 1880.  Bicycle delivery fleets include 37,000 in the [[UK]], 25,700 in [[Germany]] and 10,500 in [[Hungary]][[Police]] officers adopted the bicycle as well, initially using their own.  However, they eventually became a standard issue, particularly for police in rural areas. The [[Kent]] police purchased 20 bicycles in 1896, and by 1904 there were 129 police bicycle patrols operating. Some countries retained the police bicycle while others dispensed with them for a time. Bicycle patrols are now enjoying a resurgence in many cities, as the mobility of car-borne officers is becoming increasingly limited by traffic congestion and [[Auto-free zone|pedestrianisation]]. They also have the advantages that the officers are inherently more open to the public, and the transport is quieter to permit a more stealthy approach toward suspects. The pursuit of suspects can also be assisted by a bicycle.
+
The male anger at the freedom symbolised by the New (bicycling) Woman was demonstrated when the male undergraduates of [[Cambridge University]] chose to show their opposition to the admission of women as full members of the university by hanging a woman in effigy in the main town square — tellingly, a woman on a bicycleThis was as late as 1897.<ref>http://www.newn.cam.ac.uk/about/about_history2.shtml</ref>
  
Bicycles have enjoyed substantial use as general delivery vehicles in many cities.  In the UK, this use persisted for some purposes with generations of teenagers getting their first jobs delivering newspapers by bicycle.  In [[India]], many of [[Mumbai]]'s [[Dabbawala]]s use bicycles to deliver hot lunches to the city’s workers.  In [[Bogotá]], [[Colombia]] the city’s largest bakery recently replaced most of its delivery trucks with bicycles.  Even the car industry uses bicycles.  At the huge [[Mercedes-Benz]] factory in [[Sindelfingen]], [[Germany]] workers use bicycles, colour-coded by department, to move around the factory.
+
In the 1890s the [[bicycle craze]] led to a movement for so-called [[rational dress]], which helped liberate women from corsets and ankle-length skirts and other restrictive garments, substituting the then-shocking [[bloomers (clothing)|bloomers]].
  
===Bicycles and war===
+
===Other social implications===
 +
Sociologists suggest that bicycles enlarged the [[gene pool]] for rural workers, by enabling them to easily reach the next town and increase their ''courting radius''.  In cities, bicycles helped reduce crowding in inner-city tenements by allowing workers to commute from more spacious dwellings in the suburbs. They also reduced dependence on horses, with all the knock-on effects this brought to society.  Bicycles allowed people to travel for leisure into the country, since bicycles were three times as energy efficient as walking, and three to four times as fast.
  
''Main article:  [[Bicycle infantry]]''
+
==Uses for bicycles==
 +
{{main|Cycling}}
  
The bicycle is not suited for combat, but it has been used as a method of transporting soldiers and supplies to combat zones. Bicycles were used in the [[Second Boer War]], where both sides used them for scouting. In [[World War I]], France and Germany used bicycles to move troops. In its [[1937]] invasion of China, Japan employed some 50,000 bicycle troops, and similar forces were instrumental in Japan's march through [[Malaya]] in [[World War II]].  Germany used bicycles again in World War II, while the British employed airborne ''Cycle-commandos'' with folding bikes.
+
Bicycles have been and are employed for many uses.
 
+
*Work: [[mail|mail delivery]], [[paramedic]]s, [[police]], and [[Delivery (commerce)|general delivery]].
In the [[Vietnam War]], communist forces used bicycles extensively as cargo carriers along the [[Ho Chi Minh Trail]]. There are reports of mountain bicycles being used in scouting by U.S. Special Forces in the [[U.S. invasion of Afghanistan]] and in subsequent battles against the [[Taliban]]. The only country to recently maintain a regiment of bicycle troops was [[Switzerland]], who disbanded the last unit in [[2003]].
+
*Recreation: [[bicycle touring]] and [[physical fitness]].
 
+
*Military: [[Reconnaissance|scouting]], troop movement, supply of provisions, and patrol. See [[bicycle infantry]].
=== Bicycle racing ===
+
*Racing: [[Velodrome|track racing]], [[criterium]], [[goldsprint]]ing and [[time trial]] to multi-stage events like the [[Giro d'Italia]], the [[Tour de France]], and the [[Vuelta a España]].
 
+
*Utility: [[commuting]].
''Main article: [[Bicycle racing]]''
+
*Show: [[Lowrider bicycle|lowriders]] and perhaps [[tall bike]]s
 
 
Shortly after the introduction of bicycles, competitions developed independently in many parts of the world. Early races involving boneshaker style bicycles were predictably fraught with injuries. Large races became popular during the 1890's "Golden Age of Cycling", with events across Europe, and in the U.S. and Japan as well. [[Paris-Brest-Paris]] (PBP), which began in [[1891]], is the oldest bicycling event still run on a regular basis on the open road, covers over 1200 km and imposes a 90-hour time limit. The most famous of all bicycle races, and perhaps the most well-known race of any type, is the [[Tour de France]].  This began in [[1903]], and continues to capture the attention of the sporting world.
 
 
 
As the bicycle evolved its various forms, different racing formats developed.  Road races may involve both team and individual competition, and are contested in various ways. They range from the one-day road race, [[criterium]], and time trial to multi-stage events like the Tour de France and its sister events which make up cycling's [[Grand Tour (cycling)|Grand Tours]]. [[Recumbent bicycle]]s were banned from bike races in 1934 after [[Marcel Berthet]] set a new [[hour record]] in his ''Velodyne streamliner'' (49.992 km on Nov 18, 1933).  [[Velodrome]]s host short course [[track cycling]] which features mostly [[fixed-gear bicycle]]s, while [[cyclo-cross]] races are held on rugged outdoor terrain.  In the past decade, [[mountain biking|mountain bike racing]] has also reached international popularity and is even an Olympic sport.
 
 
 
=== Modal share: cycle use in modern cities ===
 
 
 
Cyclists and motorists make different demands on road design which may lead to conflicts both in politics and on the streets.  Some jurisdictions give priority to motorised traffic, for example setting up extensive one-way street systems, free-right turns, high capacity roundabouts, and slip roads.  Other cities may apply active ''traffic restraint'' measures to limit the impact of motorised transport.  In the former cases, cycling has tended to decline while in the latter it has tended to be maintained.  Occasionally, extreme measures against cycling may occur.  In [[Shanghai]], a city where bicycles were once the dominant mode of transportation, bicycle travel on city roads was actually banned temporarily in December [[2003]].
 
 
 
In areas in which cycling is popular and encouraged, cycle-parking facilities using [[bicycle rack]]s, lockable ''mini-garages'', and patrolled cycle parks are used to reduce theft.  Local governments also promote cycling by permitting the carriage of bicycles on public transport or by providing external attachment devices on public transport vehicles.  Conversely, an absence of secure cycle-parking is a recurring complaint by cyclists from cities with low modal share of cycling.
 
 
 
Extensive [[bicycle path]] systems may be found in some cities.  Such dedicated paths often have to be shared with inline skaters, scooters, skateboarders, and pedestrians. Segregating bicycle and automobile traffic in cities has met with mixed success, both in terms of safety and bicycle promotion.  At some point the two streams of traffic inevitably intersect, often in a haphazard and congested fashion. Studies have demonstrated that, due to the high incidence of accidents at these sites, such segregated schemes can actually ''increase'' the number of car-bike collisions.<sup>[[#Notes|7]]</sup>
 
 
 
===Bicycle activism===
 
Cyclists of many types form associations, both for specific interests (trails development, road maintenance, urban design, racing clubs, touring clubs, etc.) and for more global goals ([[energy conservation]], pollution reduction, promotion of fitness).  There tend to be two broad themes associated with bicycle activism: one strand of opinion tends to be more overtly political and frequently has roots in the [[environmental movement]], while the other tends to draw on the traditions of the established bicycle lobby.
 
 
 
Such groups may promote the bicycle as an alternative mode of transport and may also emphasize the potentials for energy and resource conservation and potential health benefits gained through a modal shift to cycle use from automobile use. Activists in both main camps tend also to argue for improved local and inter-city rail services and other methods of mass transportation, and also for greater provision for cycle carriage on such services.
 
 
 
Controversially, some bicycle activists and some traffic management advisors seek the construction of [[segregated cycle facilities]] for journeys of all lengths. Activists from the more established tradition tend to view such devices with suspicion and favour a more holistic approach based on planning, road design, road user education and enforcement of the existing traffic regulations.  The opposition to segregated cycle facilities has well-founded historical roots regarding the safety, practicality and intent of such systems. However, in some cases this opposition has a more ideological basis: some members of the US [[Effective Cycling|Vehicular Cycling Movement]] oppose the use of segregated cycling facilities as a matter of principle<sup>[[#Notes|8]]</sup>, and offer training courses aimed at the safe integration of cyclists into everyday urban traffic.  This is part of the ongoing [[cycle path debate]].
 
 
 
A recent focus, especially for European bicycle activists, has been opposition to compulsory [[bicycle helmet]] legislation. Their concerns have been raised by evidence suggesting that compulsory helmet laws and helmet promotion have been associated with significant reductions in bicycle use and with simultaneous increases in the risk of death or injury to individual cyclists. As a consequence, activists from both sides have put aside their differences in order to fight the helmet lobby.
 
 
 
[[Critical Mass]] is a worldwide activist movement of mass bicycle protest rides that may have more overt political overtones. While this anarchic movement is difficult to typify, it tends to incorporate the themes of increasing the road- and mind-share given by society to bicycle transport, and has historically drawn support from environmentally minded campaigners as well as many other more diverse strands of political thought. However, the particular forms of protest embraced by Critical Massers has drawn criticism from the broader streams of activism.
 
  
 
==Types of bicycle==
 
==Types of bicycle==
 +
{{main|list of bicycle types}}
 +
Bicycles can be categorized in different ways: e.g. by function, by number of riders, by general construction, by gearing or by means of propulsion. The common types include [[utility bicycle]]s, [[mountain bicycle]]s,  [[racing bicycle]]s, [[touring bicycle]]s, [[cruiser bicycle]]s, and [[BMX]] bicycles. Less common types include [[tandem bicycle|tandems]], [[recumbent bicycle|recumbents]], and [[folding bicycle|folding models]]. [[Unicycle]]s, [[tricycle]]s and [[quadracycle]]s are not strictly bicycles, as they have respectively one, three and four wheels, but are often referred to informally as "bikes" by users.
  
There are many different types of bicycle. See also [[:Category:Cycle types]].
 
  
====By function====
+
==See also==
* ''[[Mountain bicycle]]s'' are designed for off-road cycling, and include other sub-types of off-rad bicycles such as Cross Country (i.e."XC"), Downhill , and to a lesser extent Freeride bicycles. All mountain bicycles feature sturdy, highly durable frames and wheels, wide-gauge treaded tires, and cross-wise handlebars to help the rider resist sudden jolts. Some mountain bicycles  feature various types of suspension systems (e.g. coiled spring, air or gas shock), and hydraulic or mechanical disc brakes. Mountain bicycle gearing is very wide-ranging, from very low ratios to high ratios. Modern mountain bicycles typicaly have 21 to 30 gears.
+
{{wikibookspar||Bicycle repair}}
* ''[[Racing bicycle]]s'' are designed for speed, and include Road, Time Trial, and Track bicycles. They have lightweight frames and components with minimal accessories, ''dropped'' handlebars to allow for an aerodynamic riding position, narrow high-pressure tires for minimal rolling resistance and multiple gears. Racing bycycles have a relatively narrow gear range, and typically varies from medium to very high ratios, distributed across 18, 20, 27 or 30 gears. The narrow gear ratios allow racers to fine tune their gear selection so as to produce an efficient pedalling cadence.
+
{{Spoken Wikipedia-2|2006-01-04|Bicy.ogg|enter info here}}
 
+
* [[Cycling]]
Time Trial bicycles are similar to Road bicycles but are differentiated by a more aggresive frame geometry that throws the rider   
+
*[[List of bicycle types]]
to a more compact (i.e "aero") riding position. They also feature aeroynamic frames, wheels, and handlebars.
 
  
Track bicycles, a form of racing bicycle intended for indoor racing circuits, are exceptionally simplified to reduce weight. They typically have a single gear mounted to a fixed hub (i.e. no freewheel), no brakes, and are minimally adorned with other components that would otherwise be typical for a racing bicycle.
+
'''Other'''
 
+
* [[Bicycle advocacy]]
Messenger Bike, like the track bike, in regards to no gears(fixed gear) and no brakes, but riden by messengers hussling packages for law firms, advertising firms, sandwich shops, big banks, etc.  You may identify these persons by "reckless" operation of a bike, rudeness, and general disregard to others. Yes thats how we like it....  But the bike itself is fun to ride, and you actually become one with the bicycle.  Your muscle is used to stop the momentum it has gained by using muscle.  just like riding a tricycle when you were a kid. These bikes are easy to maintain as well.  Also not very big on being stolen.... not a lot of people know how to ride a fixed gear bike.
+
* [[Bicycle lighting]]
 
 
[[Image:Bike refelector safety flash.JPG|thumb|A modern ''touring bicycle'', with accessories and baggage]]
 
 
 
* ''[[Randonneur]]'' or ''Audax bicycles'' are designed for [[randonnée]]s or brevet rides, and fall in between racing bicycles and those intended for touring.
 
* ''[[Touring bicycle]]s'' are designed for [[bicycle touring]] and long journeys. They are durable and comfortable, capable of transporting baggage, and may feature any type of gearing system.
 
* ''[[Utility bicycle]]s'' are designed for commuting, shopping and running errands. They employ middle or light weight frames and tires, internal [[hub gear]]ing, and a variety of helpful accessories.
 
 
 
====By number of riders====
 
* A ''[[tandem bicycle|tandem]]'' or ''twin'' has two riders.
 
* A ''triplet'' has three riders; a ''quadruplet'' has four.
 
* The largest ''multi-bike'' had 40 riders.
 
 
 
In most of these types the riders ride one behind the other. Exceptions are "The Companion", or "sociable," a side-by-side two-person bike (that converted to a single-rider) built by the Punnett Cycle Mfg. Co. in Rochester, N. Y. in the 1890s. Another bicycle rented to tourists in [[Berlin]] carries eight people seated in a circle.
 
 
 
====By general construction====
 
* A ''[[penny-farthing]]'' or ''ordinary'' has one high wheel directly driven by the pedals and one small wheel.
 
* On an ''[[upright bicycle]]'' the rider sits astride the saddle.  This is the most common type.
 
* On a ''[[recumbent bicycle]]'' the rider reclines or lies supine.
 
* A ''Pedersen'' bicycle has a bridge truss frame.
 
* A ''[[folding bicycle]]'' can be quickly folded for easy carrying, for example on public transport.
 
* A ''[[Moulton Bicycle]]'' has a traditional seating position, and utilises small diameter, high pressure tires and front and rear suspension.
 
* An ''[[exercise bicycle]]'' remains stationary; it is used for exercise rather than propulsion.
 
 
 
====By gearing====
 
* ''[[hub gear|Internal hub gearing]]'' is most common in European utility bicycles, usually ranging from [[three-speed bicycle]]s to five and seven speed options. But hub gears with eight and fourteen speeds are available as well.
 
* ''[[Shaft-driven bicycle]]s'' use a [[driveshaft]] rather than a chain to power the rear wheel.  These are often used as commuter bikes because they eliminate inconveniences associated with chains and pant-legs, but they are less efficient than chain-driven bicycles. Shaft- driven bicycles usually employ internal hub gearing.
 
* ''[[Derailleur gears]]'', featured on most racing and touring bicycles, offering from 5 to 30 speeds
 
* ''[[Single-speed bicycle]]s'' and ''[[Fixed-gear bicycle]]s'' have only one gear, and include all [[BMX]] bikes, children's bikes, crowded city messenger bikes, and many others. The fixed gear has no [[freewheel]] mechanism, so whenever the bike is in motion the pedals continue to spin.  An advantage of this is the pedals can also be used to slow down.
 
* ''[[Retro-Direct]] bicycles'' have two [[sprockets]] on the rear wheel.  By backpedaling, the secondary, usually lower, gear is engaged.
 
 
 
[[Image:Velo acrobatique 2.jpg|thumb|[[Flatland_BMX|Flatland]] rider on a BMX bike]]
 
====By sport====
 
* ''[[Track bicycle]]s'' are ultra-simple, lightweight [[Fixed-gear bicycle|fixed-gear]] bikes with no brakes, designed for [[track cycling]] on purpose-built cycle tracks, often in [[velodrome]]s.
 
* ''[[Time trial bicycle]]s'' are similar to road bicycles with an extremely aerodynamic design for use in a cycling [[time trial]].
 
* ''[[Cyclo-cross]] bicycles'' are lightweight enough to be carried over obstacles, and robust enough to be cycled through mud.
 
* ''Down-hill racers'' are a specialized type of mountain bike with a very strong frame, altered geometry, and long travel suspension. They are designed for use only on downhill tracks.
 
* ''[[BMX]]'' (bicycle motocross) bicycles have small wheels and are used for [[BMX racing]], as well as for [[wheelie]]s, jumps, and other acrobatics.
 
* ''[[Triathlon]]'' bicycles have seat posts that are closer to vertical than the seat posts on road racing bicycles. This concentrates the effort of cycling in the [[quadriceps]] muscles, sparing the other large muscles of the leg for the running segment of the race. Triathlon bicycles also have specialized handlebars known as [[triathlon bars]] or aero bars.
 
 
 
====By means of propulsion====
 
* A ''pedal cycle'' is driven by pedals.
 
* A ''hand-cranked bicycle'' is driven by a hand crank.
 
* A ''rowing bicycle'' is driven by a rowing action using both arms and legs.
 
* An ''[[Motorized biccyle|motorized bicycle]]'' assists the rider with a powered motor.
 
* A ''[[moped]]'' propels the rider with a motor, but includes bicycle pedals for human propulsion.
 
* ''Shaft drive'' bicycles connect the pedals to the rear hub with a shaft instead of a chain.
 
* a "Flywheel" uses stored kinetic energy.
 
 
 
====Other types====
 
* ''[[Hybrid bicycle]]s'' are a compromise between the mountain and racing style bicycles which replaced European-style ''utility bikes'' in North America in the early [[1990]]s. They have a light frame, medium gauge wheels, and derailleur gearing, and feature straight or curved-back, ''touring'' handlebars for more upright riding.
 
* ''[[Cruiser bicycle]]s''  are designed for comfort, with curved back handlebars, padded seats, and ''balloon'' tires.  Cruisers typically have minimal gearing and are often available for rental at beaches and parks which feature flat terrain.
 
* ''[[Freight bicycle]]s'' are designed for transporting large or heavy loads.
 
* ''[[Cycle rickshaw]]s'' (also called ''pedicabs'' or ''trishaws'') are used to transport passengers for hire.
 
* ''[[Velomobile]]s'' or ''bicycle cars'' provide enclosed pedal-powered transportation.
 
* ''[[Clown bike]]s are designed for comedic effect or stunt riding. Some types of clown bicycles are:
 
** ''bucking bike'' (with one or more eccentric wheels)
 
**''tall bike'' (often called an ''upside down bike'', constructed so that the pedals, seat and handlebars are all higher than normal) — other types tall bikes are made by welding two more more bicycle frames on top of each other, and running additional chains from the pedals to the rear wheel.
 
**''Come-apart bike'', (essentially a unicycle, plus a set of handlebars attached to forks and a wheel).
 
::Clown bikes are also built that are directly geared, with no freewheeling, so that they may be pedaled backwards. Some are built very small but are otherwise normal.
 
 
 
* [[Art bike]]s: Some bikes are built so that the frame appears to be made of junk or found objects: [[Bongo the Clown]] built several ridable parade bikes which were as much kinetic sculptures as transport.
 
 
 
* A ''[[unicycle]]'' is not a bicycle, as it has only one wheel, but it is related.
 
 
 
==Standards==
 
 
 
A number of formal and industry standards exist for bicycle components, to help make spare parts exchangeable:
 
 
 
* [[ISO 5775]] Bicycle tire and rim designations
 
* ISO 8090 Cycles &mdash; Terminology (same as BS 6102-4)
 
 
 
== See also ==
 
 
* [[Bicycle lock]]
 
* [[Bicycle lock]]
* [[Bicycle messenger]]
+
* [[Bicycle rack]]
* [[Clown bicycle]]  
+
* [[Bicycle rollers]]
* [[Countersteering]]
+
* [[Bicycle safety]]
* [[Cycling]]
+
* [[Bicycling terminology]]  
* [[Cycling hand signals]]
 
 
* [[French bicycle industry]]
 
* [[French bicycle industry]]
 +
* [[Full Fairing]] - covering canopies for bicycles
 
* [[List of bicycle manufacturers]]
 
* [[List of bicycle manufacturers]]
 +
* [[List of bicycle parts]]
 
* [[List of environment topics]]
 
* [[List of environment topics]]
 
* [[List of important cycling events]]
 
* [[List of important cycling events]]
* [[Mountain biking]]
+
* [[Local bike shop]]
* [[Quadricycle]]
+
* [[Safety standards]]  
* [[Raleigh Chopper]]
 
* [[Segregated cycle facilities]]
 
* [[Safety standards]]
 
 
* [[Timeline of transportation technology]]
 
* [[Timeline of transportation technology]]
* [[Tricycle]]
+
* [[Trampe bicycle lift]]
* [[Urban bicycling]]
 
* [[Vehicular cycling]]
 
  
 
==Notes==
 
==Notes==
*1 [[Scientific American]], March 1973: "Bicycle Technology", by S.S.Wilson.
+
<div class="references-small">
*2 [http://www.jhu.edu/~gazette/1999/aug3099/30pedal.html "Johns Hopkins Gazette", Aug.30, 1999]
+
<references/>
*3 "The Stability of the Bicycle", David Jones, "Physics Today", April 1970: pp.34-40 (external link, below)
+
</div>
 +
<!-- The following notes were found to not be in use when converting to cite.php:
 +
*3 "The Stability of the Bicycle," David Jones, "Physics Today," April 1970: pp.34-40 (external link, below)
 
*4 Townsend (external link, below)
 
*4 Townsend (external link, below)
*5 [[The Economist]], Feb.15, 2003
 
 
*6 "Cities for Cyclists" (external link, below)
 
*6 "Cities for Cyclists" (external link, below)
*7 "Bicycling Life"  (external link, below)
+
*8 [[Effective Cycling]], John Forester
*8 "John Forester's Effective Cycling"  (external link, below)
+
—>
*9 See Chapter 9 of "Bicycling Science" (Reference, below) for details of transmission efficiency.
 
  
 
==References==
 
==References==
{{wikibookspar||Bicycle repair}}
 
 
* ''All About Bicycling'', Rand McNally.
 
* ''All About Bicycling'', Rand McNally.
* ''The New Columbia Encyclopedia''
+
<!--* ''The New Columbia Encyclopedia'' (This reference is overly broad) —>
 
* Richard Ballantine, ''Richard's Bicycle Book'', Pan, 1975.
 
* Richard Ballantine, ''Richard's Bicycle Book'', Pan, 1975.
 
* Caunter C. F. ''The History and Development of Cycles'' Science Museum London 1972.
 
* Caunter C. F. ''The History and Development of Cycles'' Science Museum London 1972.
* Daniel Kirshner.  ''Some nonexplanations of bicycle stability''.  American Journal of Physics, 48(1), 1980.  The abstract reads "In this paper we attempt to verify a nongyroscopic theory of bicycle stability, and fail".
+
* Daniel Kirshner.  ''Some nonexplanations of bicycle stability''.  American Journal of Physics, 48(1), 1980.  The abstract reads "In this paper we attempt to verify a nongyroscopic theory of bicycle stability, and fail."
 
* David B. Perry, ''Bike Cult: the Ultimate Guide to Human-powered Vehicles'', Four Walls Eight Windows, 1995.
 
* David B. Perry, ''Bike Cult: the Ultimate Guide to Human-powered Vehicles'', Four Walls Eight Windows, 1995.
 
* Roni Sarig, ''The Everything Bicycle Book'', Adams Media Corporation, 1997
 
* Roni Sarig, ''The Everything Bicycle Book'', Adams Media Corporation, 1997
* {{Web reference | title=Randonneurs USA | work=PBP: Paris-Brest-Paris | URL=http://www.rusa.org/pbp.html | date=March 31 | year=2005}}
+
* {{cite web | title=Randonneurs USA | work=PBP: Paris-Brest-Paris | url=http://www.rusa.org/pbp.html | date=March 31 | year=2005}}
*US Department of Transportation, Federal Highway Administration. "America's Highways 1776-1976", pp. 42-43. Washington, DC, US Government Printing Office.
+
*US Department of Transportation, Federal Highway Administration. "America's Highways 1776-1976," pp. 42-43. Washington, DC, US Government Printing Office.
 
* David Gordon Wilson, ''Bicycling Science'', MIT press, ISBN 0-262-73154-1
 
* David Gordon Wilson, ''Bicycling Science'', MIT press, ISBN 0-262-73154-1
 +
* David V. Herlihy, ''Bicycle: The History'', Yale University Press, 2004
 +
* Frank Berto, ''The Dancing Chain: History and Development of the Derailleur Bicycle'', San Francisco: Van der Plas Publications, 2005, ISBN 1-892495-41-4.
 +
* ''The Data Book: 100 Years of Bicycle Component and Accessory Design'', San Francisco: Van der Plas Publications, 2005, ISBN 1-892495-01-5.
 +
* {{cite web|url=http://www.didyouknow.cd/bicycles.htm |title=Bicycle facts |accessdate=2006-07-25}}
  
 
==External links==
 
==External links==
{{commonscat|Bicycle}}
+
 
* The World's Bicycle Conference:  [http://www.velomondial.net Velo Mondial]
+
* [http://www.OldRoads.com/ Menotomy Vintage Bicycles] - Databases of antique bicycle photos, features, price guide and research tools. Very large archives.
* The World's Data Base for Cycling Expertise: [http://www.velo.info Velo.Info ]
+
* [http://sheldonbrown.com/ Brown, Sheldon] (2005). Extensive Online [http://sheldonbrown.com/glossary.html Bicycle Glossary]  
* BikeForums.net (2005). [http://www.bikeforums.net/ BikeForums]. Retrieved March 30, 2005.
+
* Exploratorium (2004). [http://www.exploratorium.edu/cycling/humanpower1.html Science of Cycling: Human Power]. Retrieved March 30 2005.
* [http://sheldonbrown.com/ Brown, Sheldon] (2005). Extensive online [http://sheldonbrown.com/glossary.html bicycle glossary].
+
* Hudson, William (2003). [http://www.jimlangley.net/ride/bicyclehistorywh.html Myths and Milestones in Bicycle Evolution]. Retrieved March 30 2005.
* Bryan (2004). [http://www.battewell.freeserve.co.uk/bike.html Bryan's Bicycle Page]. Retrieved March 30, 2005.
 
* Croydon Cycling Campaign (2003). [http://www.croydon-lcc.org.uk/info/help.htm Information & Help]. Retrieved March 30, 2005.
 
* eHow, Inc. (2005). [http://www.ehow.com/how_228_make-bike-fit.html  How to Make Your Bike the Perfect Fit]. Retrieved March 30, 2005.
 
* Learn to Bicycle (2005). [http://www.tc.umn.edu/~hause011/article/Learn_to_Ride_Bike.html Learn to Bike, no training wheels].
 
* European Cyclists' Federation (2002). [http://www.ecf.com/networks/net_cities1.htm  Cities for Cyclists]. Retrieved March 30, 2005.
 
* Exploratorium (2004). [http://www.exploratorium.edu/cycling/humanpower1.html Science of Cycling: Human Power]. Retrieved March 30, 2005.
 
*  [http://www.atob.org.uk Folding bikes, electric bikes, trailers, trikes and alternative transport] Retrieved June 5, 2005
 
* Gray Matter Media (1995). [http://www.synaptic.bc.ca/ejournal/BicycleTouringResources.htm The eJournal website Bicycle Touring Central]. Retrieved March 30, 2005.
 
* Hashmi, Khurram (2004). [http://www.khurramweb.com/safety.html Bicycle Safety:  Road Hazards, Accident Prevention and Risk Mitigation]. Retrieved March 30, 2005.
 
* Hudson, William (2003). [http://www.jimlangley.net/ride/bicyclehistorywh.html/ Myths and Milestones in Bicycle Evolution]. Retrieved March 30, 2005.
 
* Jelsoft Enterprises Ltd. (2005). [http://www.cyclingforum.org/forums/ CyclingForum.org]. Retrieved March 30, 2005.
 
 
* Jones, David E. H. (1970). [http://ist-socrates.berkeley.edu/~fajans/Teaching/MoreBikeFiles/JonesBikeBW.pdf The Stability of the Bicycle]. Scanned in copy for download for personal use.
 
* Jones, David E. H. (1970). [http://ist-socrates.berkeley.edu/~fajans/Teaching/MoreBikeFiles/JonesBikeBW.pdf The Stability of the Bicycle]. Scanned in copy for download for personal use.
* Killian, Michael (2004). [http://www.sidewaysbike.com/ SidewaysBike (Not Your Father's Bicycle)] Retrieved March 30, 2005.
+
* [http://www.euro.who.int/transport/modes/20021009_1 World Health Organisation pages] on transport and physical activity
* Lessing, Hans-Erhard (1997). [http://www.cyclepublishing.com/history/leonardo%20da%20vinci%20bicycle.html The Leonardo da Vinci Bicycle Hoax]. Cycle Publishing. Retrieved March 30, 2005.
+
* [http://www.bikebiz.co.uk  Bicycle trade news] UK point of view
* Townsend, Andy (2005). [http://www.rider-ed.com/tips/motorcyclestability.htm Motorcycle Stability and Steering]. Rider Education of New Jersey, Inc. Retrieved March 30, 2005.
+
* [http://www.bicycleretailer.com  Bicycle trade news] US point of view
* Transportation Alternatives (2005). [http://www.transalt.org/blueprint/chapter15/index.html The advocates for cycling, walking, and environmentally sensible transportation] Retrieved March 30, 2005.
+
* [http://www.bikeforall.net Cycling links] as collected and rated in Britain
* Wachtel, Alan; Lewiston, Diana (2000). [http://www.bicyclinglife.com/Library/riskfactors.htm Risk Factors for Bicycle-Motor Vehicle Collisions at Intersections]. Bicycling Life Website. Retrieved March 30, 2005.
+
 
 +
{{Energy Transportation}}
 +
{{Sustainability and energy development group}}
  
 
[[Category:Physical sciences]]
 
[[Category:Physical sciences]]
[[Category:Technology]]
+
[[Category:Transportation technology]]
[[Category:Consumer goods]]
 
[[Category:Cycling]]
 
[[Category:Cycle types]]
 
[[Category:Human powered vehicles]]
 
[[Category:National Toy Hall of Fame]]
 
 
 
{{link FA|ru}}
 
{{link FA|uk}}
 
 
 
[[be:Ровар]]
 
[[bg:Велосипед]]
 
[[ca:Bicicleta]]
 
[[cs:Jízdní kolo]]
 
[[da:Cykel]]
 
[[de:Fahrrad]]
 
[[es:Bicicleta]]
 
[[eo:Biciklo]]
 
[[fr:Bicyclette]]
 
[[ga:Rothar]]
 
[[io:Biciklo]]
 
[[id:Sepeda]]
 
[[is:Reiðhjól]]
 
[[it:Bicicletta]]
 
[[he:אופניים]]
 
[[hu:Kerékpár]]
 
[[nl:Fiets]]
 
[[ja:自転車]]
 
[[no:Sykkel]]
 
[[nn:Sykkel]]
 
[[pl:Rower]]
 
[[pt:Bicicleta]]
 
[[ru:Велосипед]]
 
[[simple:Bicycle]]
 
[[sk:Bicykel]]
 
[[sl:Dvokolo]]
 
[[sr:Бицикл]]
 
[[fi:Polkupyörä]]
 
[[sv:Cykel]]
 
[[tr:Bisiklet]]
 
[[uk:Велосипед]]
 
[[zh:腳踏車]]
 
  
{{credit|27687777}}
+
{{credit|118309044}}

Revision as of 20:59, 27 March 2007

For other uses, see Bicycle (disambiguation).
This racing bicycle is built using lightweight, shaped aluminium tubing and carbon fiber stays and forks. It sports a drop handlebar and thin tires and wheels for efficiency and aerodynamics.
Dutch utility bicycle featuring rear internal hub brake, chaincase and mudguards, kickstand for parking, permanently attached dynamo-powered lamps and touring handlebars.
This mountain bicycle features oversized tires, a full-suspension frame, two disc brakes and handlebars oriented perpendicular to the bike's axis

A bicycle, or bike, is a pedal-driven, human-powered vehicle with two wheels attached to a frame, one behind the other.

First introduced in nineteenth-century Europe, bicycles now number over one billion worldwide,[1] providing the principal means of transportation in many regions, notably China and the Netherlands. They are also a popular form of recreation, and have been adapted for use in many other fields of human activity, including children's toys, adult fitness, military and police applications, courier services, and cycle sports.

The basic shape and configuration of a typical bicycle's frame, wheels, pedals, saddle, and handlebars have hardly changed since the first chain-driven model was developed around 1885,[2] although many important details have since been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for individuals who pursue a particular type of cycling.

The bicycle has affected history considerably, in both the cultural and industrial realms. In its early years, bicycle construction drew on pre-existing technologies; more recently, bicycle technology has, in turn, contributed ideas in both old and newer areas.

History

Drais' 1817 design made to measure
A penny-farthing or ordinary bicycle photographed in the Škoda museum in the Czech Republic.
Bicycle in Plymouth at the start of the twentieth century.

Through the centuries, several inventors and innovators contributed to the development of the bicycle. Its earliest known forebears were called velocipedes, and included many types of human-powered vehicles. The first documented ancestor of the modern bicycle, first introduced to the public in Paris by the German Baron Karl von Drais in 1818.[3] These were known as pushbikes, Draisines or "hobby horses." It was powered by the action of the rider's feet pushing against the ground. The Draisienne had two in-line wheels connected by a wooden frame. The rider sat astride and pushed it along with his feet, while steering the front wheel.

Scottish blacksmith Kirkpatrick MacMillan refined this in 1839 by adding a mechanical crank drive to the rear wheel, thus creating the first true "bicycle" in the modern sense. In the 1850s and 1860s, Frenchmen Ernest Michaux and Pierre Lallement took bicycle design in a different direction, placing the pedals on an enlarged front wheel. Their creation, which came to be called the "Boneshaker" or "penny-farthing" (more formally an ordinary bicycle), featured a heavy steel frame on which they mounted wooden wheels with iron tires. The primitive bicycles of this generation were difficult to ride, and the high seat and poor weight distribution made for dangerous falls.

The subsequent dwarf ordinary addressed some of these faults by adding gearing, reducing the front wheel diameter, and setting the seat further back, with no loss of speed. Having to both pedal and steer via the front wheel remained a problem. Starley's nephew, J. K. Starley, J. H. Lawson, and Shergold solved this problem by introducing the chain drive. These models were known as dwarf safeties, or safety bicycles, for their lower seat height and better weight distribution. Starley's 1885 Rover is usually described as the first recognizably modern bicycle. Soon, the seat tube was added, creating the double-triangle, diamond frame of the modern bike.

New innovations increased comfort, and ushered in the 1890s Golden Age of Bicycles. In 1888, Scotsman John Boyd Dunlop introduced the pneumatic tire, which soon became universal. Soon after, the rear freewheel was developed, enabling the rider to coast without the pedals spinning out of control. This refinement led to the 1898 invention of coaster brakes. Derailleur gears and hand-operated, cable-pull brakes were also developed during these years, but were only slowly adopted by casual riders. By the turn of the century, bicycling clubs flourished on both sides of the Atlantic, and touring and racing were soon extremely popular.

Bicycles and horse buggies were the two mainstays of private transportation just prior to the automobile, and the grading of smooth roads in the late 19th century was stimulated by the wide use of these devices.

Technical aspects

File:Bicycle.jpg
Reflectors for night riding are among various safety accessories available.

Legal requirements

The 1968 Vienna Convention on Road Traffic considers a bicycle to be a vehicle, and a person controlling a bicycle is considered a driver. The traffic codes of many countries reflect these definitions and demand that a bicycle satisfy certain legal requirements, sometimes even including licensing, before it can be used on public roads. In many jurisdictions it is an offence to use a bicycle that is not in roadworthy condition. In most places, bicycles must have functioning front and rear lights, or lamps, when ridden after dark. As some generator or dynamo-driven lamps only operate while moving, rear reflectors are frequently also mandatory. Since a moving bicycle makes very little noise, in many countries bicycles must have a warning bell for use when approaching pedestrians, equestrians and other bicyclists.

Standards

A number of formal and industry standards exist for bicycle components, to help make spare parts exchangeable:

  • ISO 5775 Bicycle tire and rim designations
  • ISO 8090 Cycles — Terminology (same as BS 6102-4)
  • ISO 4210 Cycles — Safety requirements for bicycles

Construction and parts

Frame

Nearly all modern upright bicycles feature the diamond frame, a truss, consisting of two triangles: the front triangle and the rear triangle. The front triangle consists of the head tube, top tube, down tube and seat tube. The head tube contains the headset, the set of bearings that allows the fork to turn smoothly for steering and balance. The top tube connects the head tube to the seat tube at the top, and the down tube connects the head tube to the bottom bracket. The rear triangle consists of the seat tube and paired chain stays and seat stays. The chain stays run parallel to the chain, connecting the bottom bracket to the rear dropouts. The seat stays connect the top of the seat tube at or near the same point as the top tube) to the rear dropouts.

Bike on the beach in Goa, India

Historically, women's bicycle frames had a top tube that connected in the middle of the seat tube instead of the top, resulting in a lower standover height at the expense of compromised structural integrity, since this places a strong bending load in the seat tube, and bicycle frame members are typically weak in bending. This design purportedly allows the rider to mount and dismount in a dignified way while wearing a skirt or dress, an action made difficult by a properly-sized diamond frame. While some women's bicycles continue to use this frame style, there is also a hybrid form, the mixte or step-through frame, which splits the top tube into two small top tubes that bypass the seat tube and connect to the rear dropouts. The ease of stepping through is also appreciated by those with limited flexibility or other joint problems. Unfortunately for the old tall man, because of its persistent image as a "women's" bicycle, the vast majority of mixte frames are quite small.

Historically, materials used in bicycles have followed a similar pattern as in aircraft, the goal being strength and low weight. Since the late 1930s alloy steels have been used for frame and fork tubes in higher quality machines. Celluloid found application in mudguards, and aluminium alloys are increasingly used in components such as handlebars, seat post, and brake levers. In the 1980s aluminium alloy frames became popular, and their affordability now makes them common. More expensive carbon fiber and titanium frames are now also available, as well as advanced steel alloys.

Drivetrain

Shimano XT rear derailleur on a mountain bike

The drivetrain begins with pedals which rotate the cranks, which connect to the bottom bracket. Attached to the (usually right) crank arm may be one or more chainrings or sprockets which drive the chain, which in turn rotates the rear wheel via the rear sprockets (cassette or freewheel). Various gearing systems may be interspersed between the pedals and rear wheel; these gearing systems vary the number of rear wheel revolutions produced by each turn of the pedals.

Since cyclists' legs produce a limited amount of power most efficiently over a narrow range of cadences, a variable gear ratio is helpful to maintain an optimum pedalling speed while covering varied terrain.

The fundamental working/application of a rear gear is explained as follows. When the bicycle chain is linked to a freewheel with higher radius (the lower gear) every cycle on the pedal leads to fewer rotations in the freewheel (and hence the rear wheel). This results in covering lesser distance for each pedal cycle. The primary source of tiredness in bicycling is the power that the rider dissipates and not the energy (for instance, a person covering a mile at 1 mile per hour will get less tired than a person covering a mile at 10 miles an hour, even though both spend the same energy). Thus power lost indicates the effort spent. In an upslope, the energy needed to cover a distance is greater than that needed on a flat surface for the same distance. Thus to maintain the same effort (or power lost) even while riding on an upslope, a rider should shift to a lower gear with the pedalling speed maintained at the same level as that on a flat surface. This adjustment increases the time taken to cover the considered distance. Thus more time is spent in dissipating the higher energy needed in an upslope. This helps to maintain a power (or effort) same as that of a flat surface. The dual of this strategy where the rider shifts to a higher gear can be used to increase the speed of travel at the cost of increased power dissipation. Gears, hence, give the rider a provision to choose a desired speed at the cost of effort and vice versa.

Road bicycles have close set multi-step gearing, which allows very fine control of cadence, while utility cycles offer fewer, more widely spaced speeds. Mountain bikes and most entry-level road racing bikes may offer an extremely low gear to facilitate climbing slowly on steep hills.

Steering and seating

The handlebars turn the fork and the front wheel via the stem, which articulates with the headset. Three styles of handlebar are common. Upright handlebars, the norm in Europe and elsewhere until the 1970s, curve gently back toward the rider, offering a natural grip and comfortable upright position. Drop handlebars are "dropped," offering the cyclist either an aerodynamic "crouched" position or a more upright posture in which the hands grip the brake lever mounts. Mountain bikes feature a straight handlebar, which helps prevent the rider from pitching over the front in case of sudden deceleration.

Variations on these styles exist. Bullhorn style handlebars are often seen on modern time trial bicycles, equipped with two forward-facing extensions, allowing a rider to rest the entire forearm on the bar. These are usually used in conjunction with the aero bar, a pair of forward-facing extensions spaced close together, to promote better aerodynamics. The Bullhorn was banned from ordinary road racing because it is difficult for the rider to control in bike traffic.

Saddles also vary with rider preference, from the cushioned ones favoured by short-distance riders to narrower saddles which allow more free leg swings. Comfort depends on riding position. With comfort bikes and hybrids the cyclist sits high over the seat, their weight directed down onto the saddle, such that a wider and more cushioned saddle is preferable. For racing bikes where the rider is bent over, weight is more evenly distributed between the handlebars and saddle, and the hips are flexed, and a narrower and harder saddle is more efficient.

A recumbent bicycle has a reclined chair-like seat that is more comfortable than a saddle, especially for riders who suffer from certain types of back pain.

Brakes

Semi low-profile cantilever brake

Modern bicycle brakes are either rim brakes, in which friction pads are compressed against the wheel rims, internal hub brakes, in which the friction pads are contained within the wheel hubs, or disc brakes. A rear hub brake may be either hand-operated or pedal-actuated, as in the back pedal coaster brakes which were the rule in North America until the 1960s, and are still common in children's bicycles. Hub drum brakes do not cope well with extended braking, so rim or disc brakes are favored in hilly terrain. With hand-operated brakes, force is applied to brake handles mounted on the handle bars and then transmitted via Bowden cables or hydraulic lines to the friction pads. Disc brakes appeared in the late 1990s on some off-road bicycles, tandems and recumbent bicycles, but are considered impractical on road bicycles, which rarely encounter conditions where the advantages of discs are significant.

For track cycling, track bicycles do not have brakes. Brakes are not required for riding on a track because all riders ride in the same direction and there are no corners or other traffic. Track riders are still able to slow down because all track bicycles are fixed-gear, meaning that there is no freewheel. Without a freewheel, coasting is impossible, so when the rear wheel is moving, the crank is moving. To slow down one may apply resistance to the pedals. Cyclists who ride a track bike without brake(s) on the road can also slow down by skidding, by unweighting the rear wheel and applying a backwards force to the pedals, causing the rear wheel to lock up and slide along the road. Most track bike frames and forks do not have holes for mounting brakes, although with their increasing popularity among some road cyclists, some manufacturers have designed their track frames to enable the fitting of brakes.

Suspension

Bicycle suspension refers to the system or systems used to suspend the rider and all or part of the bicycle in order to protect them from the roughness of the terrain over which they travel. Bicycle suspension are used primarily on mountain bicycles, but are also common on hybrid bicycles, and can even be found on some road bicycles.

Accessories and repairs

Some components, which are often optional accessories on sports bicycles, are standard features on utility bicycles to enhance their usefulness and comfort. Chainguards and mudguards, or fenders, protect clothes and moving parts from oil and spray. Kick stands help with parking. Front-mounted wicker or steel baskets for carrying goods are often used. Rear racks or carriers can be used to carry items such as school satchels. Parents sometimes add rear-mounted child seats and/or an auxiliary saddle fitted to the crossbar to transport children.

Touring bicycle equipped with head lamp, pump, rear rack, fenders/mud-guards, and numerous saddle-bags.

Toe-clips and toestraps, or clipless pedals, help to keep the foot planted firmly on the pedals, and enable the cyclist to pull as well as push the pedals. Technical accessories include solid-state speedometers and odometers for measuring distance. Other accessories include lights, reflectors, tire pump, security lock, mirror, and horn.[4] A bicycle helmet is classified by some as an accessory,[4] but as an item of clothing by others.[5]

Many cyclists carry tool kits, containing at least a tire patch kit (and/or a spare tube), tire levers, and hex wrenches. A single tool once sufficed for most repairs. More specialised parts now require more complex tools, including proprietary tools specific for a given manufacturer. Some bicycle parts, particularly hub-based gearing systems, are complex, and many prefer to leave maintenance and repairs to professional bicycle mechanics. Others maintain their own bicycles, enhancing their enjoyment of the hobby of cycling.

It is also possible to purchase road-side assistance from companies such as the Better World Club.

Performance

In both biological and mechanical terms, the bicycle is extraordinarily efficient. In terms of the amount of energy a person must expend to travel a given distance, investigators have calculated it to be the most efficient self-powered means of transportation.[6] From a mechanical viewpoint, up to 99% of the energy delivered by the rider into the pedals is transmitted to the wheels, although the use of gearing mechanisms may reduce this by 10-15%.[7][8] In terms of the ratio of cargo weight a bicycle can carry to total weight, it is also a most efficient means of cargo transportation.

A human being travelling on a bicycle at low to medium speeds of around 10-15 mph (16-24 km/h), using only the energy required to walk, is the most energy-efficient means of transport generally available. Air drag, which increases with the square of speed, requires dramatically higher power outputs with increasing speed. A bicycle which places the rider in a seated position, supine position or, more rarely, prone position, and which may be covered in an aerodynamic fairing to achieve very low air drag, is referred to as a recumbent bicycle or human powered vehicle. Humans create the greatest amount of drag on an upright bicycle at about 75% of the total drag.

Dynamics

A bicycle stays upright by being steered so as to keep its centre of gravity over its wheels. This steering is usually provided by the rider, but under certain conditions may be provided by the bicycle itself.

A bicycle must lean in order to turn. This lean is induced by a method known as countersteering, which can be performed by the rider turning the handlebars directly with the hands or indirectly by leaning the bicycle.

Short-wheelbase or tall bicycles, when braking, can generate enough stopping force at the front wheel in order to flip longitudinally. This action, especially if performed on purpose, is known as a stoppie or front wheelie.

Further reading

For more information on the technical aspects of bicycles, see also:

  • List of bicycle parts and Category:Bicycle parts

Social and historical aspects

Present day: Bikes are popular in Amsterdam

Economic implications

Bicycle manufacturing proved to be a training ground for other industries and led to the development of advanced metalworking techniques, both for the frames themselves and for special components such as ball bearings, washers, and sprockets. These techniques later enabled skilled metalworkers and mechanics to develop the components used in early automobiles and aircrafts. J. K. Starley's company became the Rover Cycle Company Ltd. in the late 1890s, and then the Rover auto maker. The Morris Motor Company (in Oxford) and Škoda also began in the bicycle business, as did the Wright Brothers.[9]

In general, U.S. and European cycle manufacturers used to assemble cycles from their own frames and components made by other companies, although very large companies (such as Raleigh) used to make almost every part of a bicycle (including bottom brackets, axles, etc.) In recent years, those bicycle makers have greatly changed their methods of production. Now, almost none of them produce their own frames. Many newer or smaller companies only design and market their products; the actual production is done by eastern companies. For example, some sixty percent of the world's bicycles are now being made in China. Despite this shift in production, as nations such as China and India become more wealthy, their own use of bicycles has declined due to the increasing affordability of cars and motorcycles. One of the major reasons for the proliferation of Chinese-made bicycles in foreign markets is the lower cost of labour in China.[10]

Female emancipation

Woman with bicycle, 1890s

The diamond-frame safety bicycle gave women unprecedented mobility, contributing to their emancipation in Western nations. As bicycles became safer and cheaper, more women had access to the personal freedom they embodied, and so the bicycle came to symbolise the New Woman of the late nineteenth century, especially in Britain and the United States.

The bicycle was recognised by nineteenth-century feminists and suffragists as a "freedom machine" for women. American Susan B. Anthony said in a New York World interview on February 2 1896: "Let me tell you what I think of bicycling. I think it has done more to emancipate women than anything else in the world. It gives women a feeling of freedom and self-reliance. I stand and rejoice every time I see a woman ride by on a wheel...the picture of free, untrammelled womanhood." In 1895 Frances Willard, the tightly-laced president of the Women’s Christian Temperance Union, wrote a book called How I Learned to Ride the Bicycle, in which she praised the bicycle she learned to ride late in life, and which she named "Gladys," for its "gladdening effect" on her health and political optimism. Willard used a cycling metaphor to urge other suffragists to action, proclaiming, "I would not waste my life in friction when it could be turned into momentum."

The male anger at the freedom symbolised by the New (bicycling) Woman was demonstrated when the male undergraduates of Cambridge University chose to show their opposition to the admission of women as full members of the university by hanging a woman in effigy in the main town square — tellingly, a woman on a bicycle. This was as late as 1897.[11]

In the 1890s the bicycle craze led to a movement for so-called rational dress, which helped liberate women from corsets and ankle-length skirts and other restrictive garments, substituting the then-shocking bloomers.

Other social implications

Sociologists suggest that bicycles enlarged the gene pool for rural workers, by enabling them to easily reach the next town and increase their courting radius. In cities, bicycles helped reduce crowding in inner-city tenements by allowing workers to commute from more spacious dwellings in the suburbs. They also reduced dependence on horses, with all the knock-on effects this brought to society. Bicycles allowed people to travel for leisure into the country, since bicycles were three times as energy efficient as walking, and three to four times as fast.

Uses for bicycles

Bicycles have been and are employed for many uses.

  • Work: mail delivery, paramedics, police, and general delivery.
  • Recreation: bicycle touring and physical fitness.
  • Military: scouting, troop movement, supply of provisions, and patrol. See bicycle infantry.
  • Racing: track racing, criterium, goldsprinting and time trial to multi-stage events like the Giro d'Italia, the Tour de France, and the Vuelta a España.
  • Utility: commuting.
  • Show: lowriders and perhaps tall bikes

Types of bicycle

Bicycles can be categorized in different ways: e.g. by function, by number of riders, by general construction, by gearing or by means of propulsion. The common types include utility bicycles, mountain bicycles, racing bicycles, touring bicycles, cruiser bicycles, and BMX bicycles. Less common types include tandems, recumbents, and folding models. Unicycles, tricycles and quadracycles are not strictly bicycles, as they have respectively one, three and four wheels, but are often referred to informally as "bikes" by users.


See also

Wikibooks
Wikibooks has more about this subject:
Listen to this article (2 parts) · (info)
Spoken Wikipedia
This audio file was created from an article revision dated 2006-01-04, and may not reflect subsequent edits to the article. (Audio help)
More spoken articles
  • Cycling
  • List of bicycle types

Other

  • Bicycle advocacy
  • Bicycle lighting
  • Bicycle lock
  • Bicycle rack
  • Bicycle rollers
  • Bicycle safety
  • Bicycling terminology
  • French bicycle industry
  • Full Fairing - covering canopies for bicycles
  • List of bicycle manufacturers
  • List of bicycle parts
  • List of environment topics
  • List of important cycling events
  • Local bike shop
  • Safety standards
  • Timeline of transportation technology
  • Trampe bicycle lift

Notes

  1. DidYouKnow.cd. There are about a billion bicycles in the world. Retrieved 30 July 2006.
  2. Herlihy, David V. (2004). Bicycle: the history. Yale University Press, 200-250. ISBN 0-300-10418-9. 
  3. Canada Science and Technology Museum: Baron von Drais’ Bicycle (2006). Retrieved 2006-12-23.
  4. 4.0 4.1 Bluejay, Michael. Safety Accessories. Bicycle Accessories. BicycleUniverse.info. Retrieved 2006-09-13.
  5. The Essentials of Bike Clothing. About Bicycling. About.com. Retrieved 2006-09-13.
  6. "Bicycle Technology," S.S. Wilson, Scientific American, March 1973
  7. "Johns Hopkins Gazette", 30 August 1999
  8. Whitt, Frank R. and David G. Wilson (1982). Bicycling Science, Second edition, Massachusetts Institute of Technology, 277-300. ISBN 0-262-23111-5. 
  9. The Wrights' bicycle shop (2007). Retrieved 2007-02-05.
  10. The Economist, 15 February 2003
  11. http://www.newn.cam.ac.uk/about/about_history2.shtml

References
ISBN links support NWE through referral fees

  • All About Bicycling, Rand McNally.
  • Richard Ballantine, Richard's Bicycle Book, Pan, 1975.
  • Caunter C. F. The History and Development of Cycles Science Museum London 1972.
  • Daniel Kirshner. Some nonexplanations of bicycle stability. American Journal of Physics, 48(1), 1980. The abstract reads "In this paper we attempt to verify a nongyroscopic theory of bicycle stability, and fail."
  • David B. Perry, Bike Cult: the Ultimate Guide to Human-powered Vehicles, Four Walls Eight Windows, 1995.
  • Roni Sarig, The Everything Bicycle Book, Adams Media Corporation, 1997
  • Randonneurs USA. PBP: Paris-Brest-Paris (March 31).
  • US Department of Transportation, Federal Highway Administration. "America's Highways 1776-1976," pp. 42-43. Washington, DC, US Government Printing Office.
  • David Gordon Wilson, Bicycling Science, MIT press, ISBN 0-262-73154-1
  • David V. Herlihy, Bicycle: The History, Yale University Press, 2004
  • Frank Berto, The Dancing Chain: History and Development of the Derailleur Bicycle, San Francisco: Van der Plas Publications, 2005, ISBN 1-892495-41-4.
  • The Data Book: 100 Years of Bicycle Component and Accessory Design, San Francisco: Van der Plas Publications, 2005, ISBN 1-892495-01-5.
  • Bicycle facts. Retrieved 2006-07-25.

External links

Energy Transportation   Edit
Battery electric vehicle | Bicycle | Electric power-assist system | Electric vehicle | Hydrogen vehicle | Trolleybus | Public Transport Bus rapid transit | Air car | Production battery electric vehicle | Low-energy vehicle | TWIKE | utility cycling | Vegetable oil used as fuel | Biodiesel | Bioethanol | Biogas | Biomass to liquid | Pyrolysis oil Alternative fuel | Alternative propulsion | Ecodriving

Template:Sustainability and energy development group

Credits

New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:

The history of this article since it was imported to New World Encyclopedia:

Note: Some restrictions may apply to use of individual images which are separately licensed.