Yokomo BB-126-4 6x12x4mm Ball Bearing Set (4 pcs)  [BB-126-4]

Precision 6x12x4mm bearings for RC drivetrains

This Yokomo BB-126-4 pack contains four 6x12x4mm ball bearings made in steel for standard RC applications. They fit typical bearing seats found in wheels, differentials, motor shafts and gearbox units on electric RC models. The set of 4 pcs lets you refresh multiple wear points during routine service or quick upgrades.

Functionally, these bearings reduce rotational friction, help keep shafts aligned, and lower wear on mating parts. Replacing worn bearings with smooth running units can noticeably improve drivetrain smoothness and throttle feel without changing gear ratios or electronics.

Installation tips: confirm the inner 6mm shaft fits correctly and the 12mm outer diameter matches the housing before pressing in. Use a bearing driver or socket that presses on the outer race to avoid stressing the inner race, and check for endplay after fitting. Do not force bearings into undersized bores and use light grease or bearing oil where applicable.

Maintenance advice: listen for noise or roughness, clean contaminated bearings with an appropriate solvent, and relubricate with low-viscosity bearing oil to restore free-spin. Replace any bearing that shows pitting, excessive play, or unusual heat during normal running.