What is the benefit to having a Kush® sprocket with inbuilt cushioning? Longer gearbox and chain life, smoother shifting and peace of mind. Road bikes generally use a set of rubber dampening blocks located in the rear wheel (termed a "Cush-drive" hub) that absorb vibration and shock loading. Dirt-bikes, which were not designed to be used on road , do not. This is where Kush sprockets come in, for riding a dirt-bike on road.