Mini-Z MR-02 Replacement Ball Differential Shaft KYOSHO MZII-003 by 3Racing  [MZII-003]

Overview of the MR-02 ball differential shaft

This is a service replacement ball differential shaft for KYOSHO Mini-Z MR-02 cars, suited to the MM and RM gearbox layouts. The MZII-003 shaft acts as the rotating axle inside the ball differential cage and is intended for electric micro touring cars used in hobby environments.

Note the compatibility limit to Mini-Z MR-02 (MM) and Mini-Z MR-02 (RM) models; verify your chassis code prior to installation. The shaft locates the bearing stack and transfers drive through the balls, influencing how the differential slips and returns power to the wheels.

Fitment tips: remove the differential assembly from the transmission case, extract the old shaft and bearing stack carefully, then install this shaft in the correct orientation inside the differential cage. Reinstall your original ball bearings and shims, check preload and lateral play as per your chassis manual, and use small precision drivers for Mini-Z hardware.

Tuning note: replacing a worn shaft will revive consistent engagement but major handling changes come from adjusting grease thickness, shim spacing, and preload. Combine shaft replacement with a routine check of balls and grease for predictable lap-to-lap behaviour.