Bicycle chain

Most bicycle chains are made from plain carbon or alloy steel, but some are nickel-plated to prevent rust, or simply for aesthetics.

These had inherent reliability problems and a bit more friction (and mechanical efficiency losses) than modern chains.

With these limitations in mind, the Nevoigt brothers, of the German Diamant Bicycle Company, designed the roller chain in 1898,[1] which uses bushings.

Early examples of chain-driven bicycles include the 1869 Guillemot and Meyer,[3] the 1879 Lawson, the 1884 McCammon,[4] the 1884 Starley Rover, and the 1895 Diamant.

[5] The study, performed in a clean laboratory environment, found that efficiency was not greatly affected by the state of lubrication.

[5] A larger sprocket will give a more efficient drive because it moves the point of pressure farther away from the axle, placing less stress on the bearings, thus reducing friction in the inner wheel.

Higher chain tension was found to be more efficient: "This is actually not in the direction you'd expect, based simply on friction".

[6] Liquid lubricants penetrate to the inside of the links and are not easily displaced, but quickly attract dirt.

This can result in increased wear on the sprockets, and possibly "chain skip" on derailleur drivetrains, in which pedalling tension causes the chain to slide up over the tops of the sprocket teeth and move ("skip") to the next alignment, reducing power transfer and making pedalling uncomfortable.

[10][11] Nickel-plated chain also confers a measure of self-lubrication to its moving parts as nickel is a relatively non-galling metal.

If the chain has worn beyond this limit, the rear sprockets are also likely to wear, in extreme cases followed by the front chainrings.

[citation needed] While the exploded view diagram here shows the older type having full bushings, modern bicycle chain has "half bushings" formed into the inner side plates, referred to as "bushingless" and "bushless" by Sheldon Brown.

The Shimano 10 pitch system is incompatible with ANSI standard #40 (1/2″) e.g. chains, sprockets and so on,[15][16] and was outlawed by the Japan Keirin Association, helping in its demise.

It is broadly accepted as inadvisable to actually use the large/large and small/small gear combinations, a practice known as cross-chaining, due to chain stress and wear.

[21] Chains have also been made of stainless steel for corrosion resistance[22] and titanium for weight reduction, but they are expensive.