Sports Science: Optimal Crank Length in Track Cycling

Trends are always coming and going in cycling. Be it nutrition, attire, or equipment modifications. In recent years there has been a trend for cyclists to ride shorter cranks for various reasons. In this blog post let’s take a deeper dive into crank lengths, with a track focus.

Before starting this post I asked Burnaby Velodrome Club sprint veteran Keith Bruno what he had seen over the years with crank lengths:

When I first started racing track the consensus was “spin to win”, I’m not really sure if any studies were done, or if it was just the old school way; it worked for the time. A few years later we were experimenting with longer cranks, especially in regard to team sprint starters and the kilometer TT. Personally, I found no benefits, the times were the same. The best reason to ride various crank lengths is purely related to morphology in my opinion.

To break it down a crank is a lever that turns a chainring. The longer the leaver the less force is needed to turn it. Lever length is limited by our legs being attached to the crank via the pedals and of course not hitting the ground!

Power output is a key metric in cycling. Broken down, power is torque (how much force) times velocity (how fast). So, you can grind a big gear at a low cadence (high torque, low velocity) or spin a small gear at a high cadence (low torque, high velocity) and get the same watts. What makes track cycling unique is that, unlike road or MTB, we do not have a cassette and derailleur to change gears while racing.

Shorter cranks in track have a few advantages.

1. Because accelerations are based on increasing cadence, a smaller crank will benefit over a longer one.
2. Depending on your anatomy and flexibility, shorter cranks may allow you to get lower and be more aerodynamic. However, even for a given height, thigh and shin length differ between people and this influences optimal crank length.
3. Some cyclists find longer cranks cause their hip angle to close to much or may develop hip problems, shorter cranks can help with that.

But remember smaller is not necessarily better depending on your anatomy and the principle of levers.

What does the science say? In a study looking at trained males (VO2max ~ 60ml/kg/min) crank length (165, 170, 175) did not change peak 6sec power or cycling economy but participants felt less fatigued with the shorter cranks^[1]. Whereas in a trial examining very fit female MTBers (VO2max ~55ml/kg/min) the effect of crank lengths (170, 172.5, 175) was examined through a battery of tests. All of the tests were non-significant except for the time to reach peak power in a sprint. Here 170mm was better than 175^[2].

Unfortunately, I don’t believe in a formula that would predict your optimal crank length. There is a bit of trial and error involved and I would ride the cranks several times and test the key metrics you are interested in before making a decision.

Just remember that if you do shorten your crank to raise your saddle by a similar magnitude.

References

References

1.              Li J, Wang Q, Zhang Y, et al. Effects of Crank Length on Cycling Efficiency, Sprint Performance, and Perceived Fatigue in High-level Amateur Road Cyclists. Journal of Exercise Science & Fitness. Published online April 2025:100384. doi:10.1016/j.jesf.2025.100384

2.              Macdermid PW, Edwards AM. Influence of crank length on cycle ergometry performance of well-trained female cross-country mountain bike athletes. Eur J Appl Physiol. 2010;108(1):177-182. doi:10.1007/s00421-009-1197-0

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