This timing belts best suited for use with HKS Slide Cam-Pulley. Optimized belt strength for each engine application makes the Fine Tune Timing Belt ideal for use with HKS Slide Cam-Pulleys for high power/high RPM engine. Belt strength has been optimized for each engine application and designed to allow stable belt tension even when heat expansion occurs in the engine. Previous timing belt manufacturing techniques have involved with applying pressure from the outside to the teeth. This applies tension to teeth making them weaker. By forming a mould with the correct shape of teeth to begin with, will allow the teeth shape to be formed without compromising belt strength and can decrease the belt skipping at high torque engine. Teeth rubber is made from H-NBR grade rubber for additional strength. 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.