The Heavy Hitter Zero XB 420 Primary Chain Drive Conversion Kit is a complete drivetrain conversion built to replace the stock belt drive on the Zero XB. Designed for riders running upgraded motors or controllers who need a drivetrain that can handle serious torque without adding unnecessary weight or rolling resistance. The lightest primary chain kit on the market with the least rotating mass and resistance of any 420 kit available.
Fitment:
- Zero XB
Download Tech Sheet (Assembly & Torque Specs)
NOTE: When installing, make sure your chain tension is loose, not tight. Any chain drive should have loose chain tension. (MORE INFO HERE)
Stock belts can't handle serious torque, especially with upgraded motors or controllers, and other chain kits add unnecessary weight or resistance. After years of breaking parts and refining designs, the perfect combo was found: a 7075-T6 billet aluminum rear sprocket to keep weight down, a nitrided 52100 tool steel front sprocket for maximum durability, and a non-O-ring Japanese chain with master link to keep rolling resistance at an absolute minimum. Vulcanized rubber sprockets were tested for noise reduction but trapped dirt and mud between chain links, accelerating wear and killing performance. This kit maintains your stock gear ratio and OEM motor alignment with precision machining that extends sprocket life and keeps things smooth at high RPM. It's louder than a belt drive, but no louder than other chain kits. Race-proven on stock power and high-power EBMX, Sotion, and Torp setups.