The balancer is designed to reduce engine vibration by creating a vibration in the opposite direction to the engine. When used at high RPM such as on circuits, the vibration will naturally increase which causes more load on the balancer. Moreover, the balancer rotates at double speed of the crankshaft which will cause the belt to stretch at a faster rate compare to the other belts. This stretch will eventually put the balancer out of synchronization with the crankshaft, causing more vibration and then eventually the belt may break up. For this reason, HKS recommends that when the timing belt is changed, the balancer belt should also be changed with a strengthened item to allow the balancer for effective, accurate and reducing stress on the engine and chassis.