Crank lengths have become a hot topic of conversation in the last couple of years, with many prominent names in mountain biking adopting the mantra of shorting being better. In most instances, they're right.
Why would you want shorter cranks? With a shorter crank arm, you will have a smaller pedaling radius, which allows for a less extreme hip angle at the top of the pedal stroke and fewer pedal strikes at the bottom. This smaller pedaling radius allow for a higher cadence, which is more efficient as MTB gearing is now offered in much wider ranges.
Shorter cranks have also proven to benefit technical sections, since they will keep riders' feet closer together when the cranks are level with the ground. Longer cranks are more susceptible to strike a trail feature. The benefits of shorter cranks are becoming pretty clear in mountain biking, and many brands are beginning to meet the demand for short cranks.
Source: BikeMag
