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

Introduction to the MR-02 ball differential shaft

This replacement ball differential shaft is intended for KYOSHO Mini-Z MR-02 hobby cars, covering MM and RM variants. The MZII-003 acts as the axle within the ball differential cage and is suitable for routine repair or part replacement in electric micro touring applications.

Verify fitment against Mini-Z MR-02 (MM) and Mini-Z MR-02 (RM) chassis codes before installation. The shaft retains the bearing stack and transmits drive through the ball differential, influencing slip characteristics and the drivetrain feel during acceleration and cornering.

Installation procedure: remove the differential housing from the transmission case, extract the existing shaft and bearing stack with care, then position and install the new shaft in the correct orientation inside the differential cage. Reassemble using the original balls and shims, and check preload and end play according to your MR-02 manual. Work on a clean surface with a precision hex driver set.

Tuning note: fitting a new shaft corrects wear-related inconsistencies, but differential tuning changes are achieved through ball grease selection, shim spacing, and preload adjustments. Combine the shaft change with a full check of balls and grease to ensure predictable performance on track.