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== Description ==
[[Image:Bicycle_Wheel_Sidepose.jpg|thumb|Bicycle Wheels: Two wheels side-by-side]]
Bicycle wheels are made up of the front hub, spokes, rim, tires, and the quick release mechanism and connect to the frame and fork via dropouts. The wheel has evolved over years and serves as a key component of a bicycle. Wheelbuilding is the art and science of assembling a wheel, generally a bicycle wheel, although such wheels are also used on wheelchairs, motorcycles, and some cars.

== How it works ==

To fully understand how wheels work it is essential to understand all important components of the wheel:


'''Quick Release Mechanism:''' A quick release skewer is a lever operated cam system used with a hollow axle for securing the wheels on a bicycle. Wheels equipped with quick release skewers can be removed from the bicycle frame and replaced more quickly than wheels with solid axles and hex nuts. On the negative side, quick release axles render the wheel more vulnerable to theft. Also, care must be taken to ensure that they are properly tightened. [[Image:Bicycle_QR_Sidepose.jpg|thumb|Quick Release Mechanism]]


'''Front hub:''' The hub uses bearings, usually ball bearings, to reduce friction with the axle. Except in fixed gear bicycles, the rear hub is connected to the freewheel or freehub and the rear sprockets. Some bicycle wheels are attached to the bicycle frame using a quick release for ease of removal. 


'''Spokes:''' The rim is connected to the hub by several spokes under tension. At the end of each spoke is a nut, called a nipple that can be used to adjust the tension in that spoke. The nipple has traditionally been located at the rim, but some recent designs place it at the hub to reduce rotating mass. With rim brake-design wheels, the front spokes can be arranged radially, with 1 or more crossings or a mixture, such as with crows-foot pattern spokes. However, all disc brake-design wheels must have spokes attach to the hub tangentially, with the resulting crossing pattern, in order to transmit torque from the rim to the hub. Similarly, all rear wheels must have some spokes (typically it is all) tangential attached to the hubs, with resulting crossing patterns, to transmit the torque applied to the rear hub by the drivechain out to the rim. Wheels can have as few as a dozen or so spokes to well over 100 depending on the intended use, but traditionally most bike wheels have had 32 or 36 spokes. Fewer spokes usually means less weight and aerodynamic drag; more spokes usually means more strength. However, equal and appropriate spoke tension is the key factor to strong bicycle wheels that remain true (circular and straight). Spokes are usually round in cross-section, but high-performance wheels may use bladed (flattened or ovalized) spokes to reduce erodynamic drag.


'''Rim:''' The rim is an extrusion that is butted into itself to form a circle. Most rims are made of aluminum alloy, while some very high-end rims are made of carbon fiber, and some old or very low-end rims are made of steel. Rims have even been made of wood and thermoplastic. The number of spoke holes on the rim normally matches the number of spoke holes in the hub. Some unusual rim designs have no holes for spokes, for example Campagnolo road rims and the Velocity Zvino MTB rims. Rims meant for use with rim brakes provide a smooth braking surface, while rims meant for use with disc brakes or hub brakes sometimes lack this surface. Rims can either have a single-wall or double-wall cross section. Single-wall rims are usually less expensive and weaker; double-wall rims tend to be stronger and more expensive. Double-wall rims may have a deep profile either to reduce aerodynamic drag or for additional strength, especially in the case of few spokes. 


'''Tires:''' The tries are usually rubber made and go around the rim. Combined with all other components of the wheel they form a wheel. [[Image:tires.jpg|thumb|Tire]]


'''How It Works:''' Bicycles usually have two wheels, one in back and one in the front. While in most cases the front wheel only takes several 360 degree revolutions its the back wheel that makes the bike move. Indirectly connected to the peddal through the chains, it revolves everytime the boker exerts force on the pedal. With every full circle spin of the pedal, the wheel spins and makes the bike move forward. Known as a remarkable invention the wheel makes the bike move and is very important for a successful ride.


== Evolution of the wheels ==

Based on diagrams on ancient clay tablets, the earliest known use of this essential invention was a potter’s wheel that was used at Ur in Mesopotamia, part of modern day Iraq, as early as 3500 BC. The first use of the wheel for transportation was probably on Mesopotamian chariots in 3200 BC. It is interesting to note that wheels may have had industrial or manufacturing applications before they were used on vehicles. 


A wheel with spokes first appeared on Egyptian chariots around 2000 BC, and wheels seem to have developed in Europe by 1400 BC without any influence from the Middle East. Because the idea of the wheel appears so simple, it’s easy to assume that the wheel would have simply "happened" in every culture when it reached a particular level of sophistication. However, this is not the case. The great Inca, Aztec and Maya civilizations reached an extremely high level of development, yet they never used the wheel. In fact, there is no evidence that the use of the wheel existed among native people anywhere in the Western Hemisphere until well after contact with Europeans. 


Even in Europe, the wheel evolved little until the beginning of the nineteenth century. However, with the coming of the Industrial Revolution the wheel became the central component of technology, and came to be used in thousands of ways in countless different mechanisms.

[[Bicycle_Wheel_History]]
 
== 3D parts ==

{| border="1" align="center"
|+ '''Wheel Bill of Materials'''
! width="50"|Part # !! width="100"|Part Name !! width="50"|# Req'd !! width="150"|CAD File !! width="145"| Image
|-
! 1
|align="center"|Front Axle
| align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[front_axle.zip Contents|Front Axle]]
| align="center"|[[Image:front_axle.jpg |center|thumb|100px]]
|-
! 2
|align="center"|Front Bearing
| align="center"|2 
|align="center"|<!--GICL Bot edit:-->[[bearing_front.zip Contents|Front Bearing]]
| align="center"|[[Image:bearing_front.jpg |center|thumb|100px]]
|-
! 3
|align="center"|Washer
| align="center"|2 
|align="center"|<!--GICL Bot edit:-->[[washer_front_wheel.zip Contents|Washer]]
| align="center"|[[Image:washer_front_wheel.jpg |center|thumb|100px]]
|-
! 4
|align="center"|Inner Nut
| align="center"|2 
|align="center"|<!--GICL Bot edit:-->[[nut_1_front_wheel.zip Contents|Inner Nut]]
| align="center"|[[Image:nut_1_front_wheel.jpg |center|thumb|100px]]
|-
! 5
|align="center"|Outer Nut
| align="center"|2 
|align="center"|<!--GICL Bot edit:-->[[nut_2_front_wheel.zip Contents|Outer Nut]]
| align="center"|[[Image:nut_2_front_wheel.jpg |center|thumb|100px]]
|-
! 6
|align="center"|Front Wheel
| align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[hub_front.zip Contents|Front Wheel]]
| align="center"|[[Image:hub_front.jpg |center|thumb|100px]]
|-
! 7
|align="center"|Dustcap
|align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[dust_cap.zip Contents|Dustcap]]
| align="center"|[[Image:dust_cap.jpg |center|thumb|100px]]
|-
! 8
|align="center"|Front Tire
|align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[tire_front.zip Contents|Front Tire]]
| align="center"|[[Image:tire_front.jpg |center|thumb|100px]]
|-
! 9
|align="center"|Front Wheel Assembly
|align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[wheel_front_assem.zip Contents|Front Wheel Assembly]]
| align="center"|[[Image:wheel_front_assem.jpg|center|thumb|100px]]
|-
! 10
|align="center"|Wheel and Fork Assembly
|align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[wheel_fork_assem.zip Contents|Wheel-Fork Assembly]]
| align="center"|[[Image:wheel_fork_assem.jpg|center|thumb|100px]]
|-
! 11
|align="center"|Wheel, Fork and Frame Assembly
|align="center"|1 
|align="center"|<!--GICL Bot edit:-->[[wheel_frame_assem.zip Contents|Wheel-Frame Assembly]]
| align="center"|[[Image:wheel_frame_assem.jpg|center|thumb|100px]]
|}


Back to [[Bicycle]]


== References ==

[http://en.wikipedia.org/wiki/Quick_release_skewer Quick Release]

[http://en.wikipedia.org/wiki/Bicycle_wheel#Hub Front Hub]

[http://en.wikipedia.org/wiki/Bicycle_wheel#Hub Spokes]

[http://en.wikipedia.org/wiki/Bicycle_wheel#Hub Rim]

[http://www.ideafinder.com/history/inventions/wheel.htm Wheels History]