Bridgestone has best-in class tires engineered with advanced tire technology for those moments when you need it most. That's why their engineers are very passionate about researching and developing new tire technologies, including inner tubes. Discover the technologies that fit your performance needs. Bridgestone Heavy Duty Tubes are designed for heavy-duty street and off-road applications. Super thick for serious off-road competition, 3 mm thick. Heavy duty puncture resistance tubes for the serious off-road use. Tube Specifications: Valve stem type: TR-4 (straight metal stem (8 mm diameter)). Size: Rear 100/90-19.