Should you use the same length for a road bike and a mountain bike or cyclocross bike?
It depends. 1. Unlike most road riding, which is more steady state with consistent cadence for long periods, thus making full use of the long crank, mountain biking in technical terrain and cyclocross racing involve frequent drastic changes in cadence. Spinning the cranks back up to speed is better accomplished with a shorter crank, while powering up long climbs is best accomplished with a longer one. So I try to strike a balance between those requirements and look for crank length more like 20-21 percent of inseam length for the mountain bike or cross bike (as opposed to 21-21.6 percent of inseam for a road bike). Of course, a the same crank length as the road bike works well on a mountain bike or cross bike that is used for riding on dirt roads and relatively smooth trails. 2. I designed the bottom bracket height on the Megabike and Gigabike for a 200mm crank. On a custom hardtail or a custom full suspension bike, I can adjust this, but I highly recommend against using any longer tha
