When to Replace Mini 4WD Parts

Most Mini 4WD parts degrade gradually rather than breaking, so knowing the wear signs is what keeps a car consistent.

Gears and bearings

Rounded gear teeth and bearings that no longer spin freely are the two that cost the most speed. Both are cheap and both are worth replacing at the first sign rather than the last.

Rollers

A roller with a flat spot, a seized bearing or a worn rubber ring changes how the car meets every wall. Check them by hand before every session.

Axles and shafts

Any axle that fails a roll test on a flat surface is finished. Axles bend easily in a crash and are the most commonly overlooked wear item.

Brake sponge and tyres

Both are consumables. A brake sponge that has compressed is running less brake than it was; a tyre that has worn is running a smaller diameter and therefore different gearing.

Keep spares

The parts that wear are cheap. Carrying spares of each turns a race-ending failure into a five-minute repair.