Bicycle Chain

From GICL Wiki
Jump to: navigation, search

Contents

Description

Roller Chain

The chain on a bicycle transmits power from the pedals to the rear wheel. A chain is one of the most efficient ways to tranfer power. The type of chain used on modern bicycles is called a roller chain. The chain also gives a mechanical advantage related to the relative size of the sprockets at the front crank and the rear wheel. Multiple sprockets and a derailleur allow the rider to change gears. This enables the bicycle to reach higher speeds and also makes pedaling easier when riding on difficult terrain.


The size of a chain is determined by two quantities, pitch and length. Pitch is defined as the distance between the rollers. This distance is always 1/2" on modern bicycle chains. The width is the distance between the inner plates. There are two standard widths for bicycle chains: 1/8" for single speed bicycles and 3/32" for multi-speed, derailleur equipped bicycles.


Back to Bicycle

How it works

A chain works by transmitting power using tensile forces. A rider pedaling creates a torque which is transferred from the front crank to the rear wheel through the chain and sprockets. This turns the rear wheel and propells the bicycle forward.

Bushingless Chain

There are two common types of 1/2" x 3/32" bicycle chains. The first is the standard roller chain, already discussed. The second, a subset of the roller chain, is a bushingless chain in which the inner plates have an extrusion that allows them to act as the bushings. Bushingless chains are easy to make, move well laterally, and allow for good lubrication which is why they are the preferred choice in modern bicycles.


Chain lubrication is very important to keep the chain from rusting and to avoid wear. Liquid lubricants are the most common type of chain lubricants becuase of their ability to penetrate all parts of the chain. These liquids collect dirt and dust easily, however, so cleaning the chain frequently is necessary.


The sprockets used in bicycles are also made in standard sizes to fit the two sizes of chains. Different manufacturers produce different teeth shape, though, in an attempt to make shifting gears as quick and smooth as possible.


Back to Bicycle

Evolution of the chain

The first bicycles did not have a chain and the pedals directly turned the wheel. These bicycles had only one speed and the speed was limited by the diameter of the wheel. In attempts to achieve high speeds, bikes were built with very large front wheels, some taller than a man. These bicycles were hard to mount, not very versatile and at time dangerous.

While nearly every bike chain today is of the bushingless desgin, old types of chains include the block chain, step-link chain and the Simpson lever chain.


Back to Bicycle

3D parts

Chain Bill of Materials
Part # Part Name # Req'd CAD File Image
1 Chain 1 Chain
Chain.jpg


Back to Bicycle

References

Bicycle Chain

Roller Chain Picture

What is a Chain?

Sheldon Brown's Bicycle Glossary