Bridgestone Heavy Duty Motorcycle Tubes Bridgestone HD Tubes are designed for durability, whether on roads, trails, or racetracks, and are approved for highway and on-road use across all sizes. Features: Bridgestone's extremely tough, medium-duty inner tube Heavy-duty tubes safe for all types of motorcycle use All available sizes rated for on-road use Tough enough for the rigors of motocross or the high weight requirements of cruisers and touring bikes Engineered with the same tech as Bridgestone motocross tubes Tr-4/6 straight metal stem (8mm diameter) Bridgestone's middle thickness tube carcass Safe for on-road, Adv, MX and dual sport applications