Bicycle: Difference between revisions
imported>Nick Johnson (So much more to write.) |
imported>David Ellis (fixing spelling) |
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# [[mountain bicycle|Mountain Bicycles]] -- characterized by wide, knobby tires, shock absorbers, heavier frames, and straight handlebars. The frame generally encourages a more upright posture. | # [[mountain bicycle|Mountain Bicycles]] -- characterized by wide, knobby tires, shock absorbers, heavier frames, and straight handlebars. The frame generally encourages a more upright posture. | ||
# [[tandem bicycle|Tandem Bicycles]] -- A bicycle with two sets of handlebars, seats and transmission, to allow two people to ride at once. | # [[tandem bicycle|Tandem Bicycles]] -- A bicycle with two sets of handlebars, seats and transmission, to allow two people to ride at once. | ||
# [[ | # [[recumbent bicycle|Recumbent Bicycles]] -- A bicycle in which the rider employs a horizontal, foot-first posture. | ||
It should be noted, however, that bicycle enthusiasts have often mixed-and-matched designs and technologies, yielding bikes that are not easily classified. For instance, a tandem bicycle in which the front rider employs the | It should be noted, however, that bicycle enthusiasts have often mixed-and-matched designs and technologies, yielding bikes that are not easily classified. For instance, a tandem bicycle in which the front rider employs the recumbent position. | ||
== Parts of a Bicycle == | == Parts of a Bicycle == | ||
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==== Fixed-Gear, Fixies, and Track Bikes ==== | ==== Fixed-Gear, Fixies, and Track Bikes ==== | ||
In a fixed-gear | In a fixed-gear bicycle, the rotation of the pedals is directly coupled with the rotation of the rear wheel. There is only one available gearing ratio. Such a bicycle cannot [[coast]], nor can the rider adjust the [[gear ratio]] to accommodate changes in terrain. | ||
Such bicycles can be ridden backwards. | Such bicycles can be ridden backwards. | ||
Such bicycles are | Such bicycles are perceived as being more efficient. There are arguments that one of the major sources of inefficiency experienced by a cyclist are due to [[derailleur]] transmissions. For this reason, fixed-gear bicycles are often used in races. | ||
The rear wheel of a fixed-gear bicycle is marginally stronger than one from a multiple gear bicycle due to the wheel's [[wheel dish|dish]] -- an asymmetry in spoke structure necessitated by the width of multiple sprockets. This is also the case with single speed or internally geared bicycles. | The rear wheel of a fixed-gear bicycle is marginally stronger than one from a multiple gear bicycle due to the wheel's [[wheel dish|dish]] -- an asymmetry in spoke structure necessitated by the width of multiple sprockets. This is also the case with single speed or internally geared bicycles. | ||
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==== Disk Brakes ==== | ==== Disk Brakes ==== | ||
==== No | ==== No brakes, a la Fixed-Gear ==== | ||
When the pedals are directly coupled with the motion of the rear wheel, as is the case with fixed gear bicycles, a rider can brake by simply pedaling more slowly. For this reason, experienced fixed gear riders will often build bicycles without brakes. | When the pedals are directly coupled with the motion of the rear wheel, as is the case with fixed gear bicycles, a rider can brake by simply pedaling more slowly. For this reason, experienced fixed gear riders will often build bicycles without brakes. | ||
Revision as of 21:59, 28 February 2007
A Bicycle or bike is a machine for human transportation that employs two wheels. Unlike most modern methods of transportation, bicycles are human powered.
History of Bicycles
Types of Bicycles
There are very many types of bicycles. Most bicycles sold today fit into one of these categories:
- Road or Racing Bicycles -- characterized by narrow tires, no shock absorbers, thin light frames, and drop handlebars. The frame generally encourages a more inclined posture.
- [[hybrid bicycle|Hybrid Bicycles] -- a blanket term for bicycles which have characteristics of both Road and Mountain bicycles.
- Mountain Bicycles -- characterized by wide, knobby tires, shock absorbers, heavier frames, and straight handlebars. The frame generally encourages a more upright posture.
- Tandem Bicycles -- A bicycle with two sets of handlebars, seats and transmission, to allow two people to ride at once.
- Recumbent Bicycles -- A bicycle in which the rider employs a horizontal, foot-first posture.
It should be noted, however, that bicycle enthusiasts have often mixed-and-matched designs and technologies, yielding bikes that are not easily classified. For instance, a tandem bicycle in which the front rider employs the recumbent position.
Parts of a Bicycle
Despite its apparent simplicity, a modern bicycle is actually a very complicated machine. Each part of a bicycle has been repeatedly improved upon by more than a century of engineering.
The Frame
Main article: bicycle frame
The Wheels
Main article: bicycle wheel
The wheels of bicycles are very light weight, yet strong and flexible enough to withstand bumps. A typical bicycle wheel consists of a central hub, a plethora of spokes leading to a circular rim, and a pneumatic tire fastened to the rim. Each part of this system is much more complicated than it seems.
The Hub
Freewheel versus Cassette versus Internal Geared Hub versus Fixed gear hub versus ...
The Transmission
Main article: bicycle transmission
A human operator typically powers a bicycle by applying a force to pedals using his or her legs. The pedals are connected to a front sprocket (called the chain ring) by cams (called cranks or crank arms), which translate the linear force from the foot into a torque, thus rotating the chain ring. This torque is transmitted via a chain (transmission) to a rear sprocket (called a freewheel or cassette, depending on the technology), which is coupled to the rear wheel.
Alternatively, there are also bicycles which use a treadle mechanism in place of the pedals.
Fixed-Gear, Fixies, and Track Bikes
In a fixed-gear bicycle, the rotation of the pedals is directly coupled with the rotation of the rear wheel. There is only one available gearing ratio. Such a bicycle cannot coast, nor can the rider adjust the gear ratio to accommodate changes in terrain.
Such bicycles can be ridden backwards.
Such bicycles are perceived as being more efficient. There are arguments that one of the major sources of inefficiency experienced by a cyclist are due to derailleur transmissions. For this reason, fixed-gear bicycles are often used in races.
The rear wheel of a fixed-gear bicycle is marginally stronger than one from a multiple gear bicycle due to the wheel's dish -- an asymmetry in spoke structure necessitated by the width of multiple sprockets. This is also the case with single speed or internally geared bicycles.
Single Speed Bikes
A single speed bicycle should not be confused with a fixed-gear bicycle. A single speed bicycle features a free wheel, which allows the rear wheel to move forward while the chain remains stationary.
Internally Geared Hubs on Utility Bikes
The Derailleur
The Brakes
Most bicycles feature a method for slowing the bicycle by using friction.
Caliper Brakes
V Brakes
Disk Brakes
No brakes, a la Fixed-Gear
When the pedals are directly coupled with the motion of the rear wheel, as is the case with fixed gear bicycles, a rider can brake by simply pedaling more slowly. For this reason, experienced fixed gear riders will often build bicycles without brakes.
However, as typical bicycle chains are not designed to withstand this sort of use, it is not a good idea. Put brakes on the bike.
Bicycles in Sport
Main article: cycling