Campagnolo crankset dating
Several different formulas exist to calculate appropriate crank length for various riders.
In addition to the rider's size, another factor affecting the selection of crank length is the rider's cycling specialty and the type of cycling event.
This can eventually be a cause of crank breakage, which commonly occurs at the pedal eye.
Some manufacturers advise the use of a thin steel washer between the pedal and crank, but this is ineffective because the hard washer frets against the crank instead.
Bicycle crank length has not been easy to study scientifically for a number of reasons, chief among them being that cyclists are able to physiologically adapt to different crank lengths.
Cyclists are typically more efficient pedalling cranks with which they have had an adaptation period.
Cranks are constructed of either an aluminum alloy, titanium, carbon fiber, chromoly steel, or some less expensive steel.Tubular steel cranks (such as Tioga's Revolver) can be light and very strong, are usually found on BMX bikes, and are slowly finding their way to mountain bikes (dirt jumping and urban assault).Aluminum cranks may be cast, hot forged or cold forged ("cold" in this context means the billet from which the crank is to be made is heated to a specified temperature well below the melting point, not room temperature).For indoor unicycling such as freestyle or hockey, shorter cranks give a smoother pedaling motion and enable tighter turns without the pedal hitting the floor.Crank lengths of 100mm are common, although some riders use cranks as short as 79mm.