Mini 4WD Gear Maintenance

Gears wear gradually, and a worn set costs speed without ever obviously failing. Knowing what to look for is most of the job.

Check the mesh

Gears should turn with a smooth whirr. A grinding note means the mesh is too tight; a rattle means too loose. Both waste power, and both are usually a mounting or spacer problem rather than a gear problem.

Look for rounded teeth

Hold the gear up and look along the tooth profile. Teeth that have gone rounded or shiny at the tips no longer transmit power cleanly and will skip under load.

Deburr new gears

Fresh gears carry moulding flash that causes noise and drag. Removing it carefully, or running the gears in gently, gets a new set to its best sooner.

Replace as a set

Mixing a new gear with worn partners wears the new one quickly, because it carries load unevenly. Change the meshing gears together.