Backfire Hammer 160mm Pneumatic Tires and Parts, also work on Hammer Sledge! Options Specifications: Wheels with rim: Including 4 pieces of 160mm pneumatic tires ( inner tube and outer rubber tires), rims, and size 6000 bearings pre-installed.  Pulleys: Including 1 pair of 50 teeth pulleys with bearings pre-installed (each pulley contains one 6903 bearing and one 62900 bearings）. This pulley only works with the 160 wheels, NOT with cloud wheels or other street wheels directly.  To change wheels, you need to change belt and pulley as well.  Belts: Including 1 pair of 340-M5 high quality belts working with the Backfire Hammer 160 wheels.  Rubber Tires: 4 pieces of 160mm rubber tires only Inner Tubes: 4 pieces of inner tubes (150mm) only which fits Hammer 160mm tires.  Disclaimer: Ship without air pumped in, users have to pump the air to the recommended PSI.