HPI Baja Off-Road 18T Pinion SBJ018T Steel Upgrade by GPM  [SBJ018T]

Steel pinion for HPI Baja drivetrains

The SBJ018T is an 18-tooth steel aftermarket pinion intended as a direct replacement for HPI Baja drivetrains. Built from steel, it aims to reduce wear and maintain reliable tooth engagement for efficient power transfer between the motor and spur gear in rough off-road use.

Compatible with HPI Baja models, this 18T pinion is useful for enthusiasts who swap gear ratios for different track or trail conditions. The 18-tooth option provides a practical compromise between acceleration and top-end speed when matched with the correct spur and motor characteristics.

Fitting advice: verify clean tooth mesh and correct centre distance, confirm the motor shaft sizing, and secure the pinion with the appropriate torque. Turn the drivetrain slowly to confirm even contact and keep an eye on wear and runout during routine maintenance to preserve drivetrain performance.

This steel 18T pinion is a dependable choice for HPI Baja replacements and for methodical gear ratio testing to tune handling and speed.