In cycling circles it’s one of the most hotly debated questions. Does crank length really matter — and why? Well for starters it helps to understand what crank length is. Take a tape measure and calculate the distance from the bottom bracket spindle to the pedal spindle and you’ll have your number. Most bikes come stock with cranks that are 170mm, 172.5mm, or 175mm depending on the size of the bike. But the range is far broader than that, going from 162.5mm all the way to 177.5mm. The common sentiment is that a shorter rider will be more efficient with shorter cranks and vice versa. But does the theory hold water? Our friends at the Global Cycling Network went into the test lab to find out, measuring both peak power output and sustained threshold power with various crank lengths. Watch this video to find out what they found out.