AUTOMOTIVE V-BELTS have the important function of transferring the crankshaft rotation to the auxilliary systems. These auxilliary systems are comprised of alternator, fan, water pump, power steering, cooler, etc.Thus, in the last few years the following two requirements have become important in regard to automotive V-belts: 1) The belt tension should remain stable retaining its load transmission capacity for a long time period without it being necessary to retension the belt. 2) The actual service life of the belt should be lengthened, and belt reliability should be increased.In regard to item (1) above, the 1980 California Standard (CARB) stated that belts should provide 30,000 miles maintenance-free service (Finally, at the request of the American belt manufacturers, the requirement was changed to one adjustment in 30,000 miles). Furthermore, the 1982 Bill being prepared mentions 50,000 miles maintenance-free operation and 100,000 miles service life.Bando Chemical Industries Co. Ltd. undertook a detailed investigation of belts used so far in order to establish the conditions necessary for a belt to clear the 30,000 miles maintenance-free requirement, and the 50,000 miles service life requirement. The result is a uniquely innovative maintenance-free belt.