For: Off Road Bikes
Compatible with SRAM XO 38 x 28 sold as a set only
Scientifically proven technology that enables athletes to ride harder, longer and faster with less fatigue! By increasing the size of the gear when you are pushing the hardest (down stroke) and then decreasing it to get through the top and bottom dead zones quickly. The principle being that the force on the pedals is consistently proportional to the muscular force of the rider.