Shorter cranks reduce the distance your foot travels to make a single revolution. Imagining the circle your foot must draw ...

If leverage won bike races, we'd all be riding 400mm cranks—debunking myths and optimizing crank arm length for peak performance.

But the reason wasn’t that it’s the new ‘hot trend,’ he says. It’s just that the shorter crank arm fits her bike and body position better and makes her a more efficient rider.