How to Build Your First Tamiya Mini 4WD

A first Mini 4WD build is straightforward, but the difference between a car that runs and a car that runs well is entirely in the details you handle during assembly.

Cut and clean the parts

Cut parts from the sprue leaving a small tag, then file the tag flush. Cutting flush to the part tears the plastic and leaves a lump that stops components seating properly.

Get the gear mesh right

Gears should turn freely with a faint whirr, not a grind and not a rattle. Spin the drivetrain by hand before fitting the motor. Any tight spot you can feel by hand becomes lost speed under power.

Fit bearings squarely

Bearings and bushings must sit flat in their housings. A bearing pressed in at an angle binds the axle and costs more speed than any motor upgrade will recover.

Check before you run

Roll the assembled car across a table. It should track straight and coast. If it pulls to one side or stops quickly, fix that before adding parts.