Kyosho MA008 3-Speed Spur Gear Mad Force

This is a spur gear for the three-speed transmission on Kyosho's Mad Force monster truck platform.

A three-speed gearbox is unusual in radio control and it exists on these trucks for a reason: a monster truck this heavy needs low gearing to get moving and pull itself over obstacles, but that same gearing would leave it slow and over-revving on open ground. Shifting through the ratios lets it do both.

The spur gears inside carry the entire drivetrain load through their tooth faces, and on a heavy truck with a lot of rotating mass in the wheels those loads are substantial. Wear follows a predictable path: the tooth faces polish, then pit, then start to round off, and the gearbox gets progressively noisier under power until teeth begin to strip.

Running a worn gear against a fresh one just damages the new part, so replacing them together is the sensible approach. This is the genuine Kyosho part, so the tooth form and mesh are correct. Fitment covers the Mad Force, Mad Force Kruiser and Kruiser VE, Twin Force and Mad Crusher.