Yokomo BB-126-4 6x12x4mm RC Ball Bearings (4 pcs)  [BB-126-4]

Small 6x12x4mm bearings built for RC use

The Yokomo BB-126-4 kit contains four 6x12x4mm steel ball bearings suitable for electric RC models. These bearings are commonly used in wheel hubs, differential carriers, motor shafts and gearbox bearings. Supplied as 4 pcs so you can replace multiple wear points in one service session.

Their role is to lower rotational friction, keep shafts correctly aligned and reduce wear on mating components. Fitting new bearings often improves drivetrain smoothness and throttle response without any changes to gear ratios or electronics.

Installation advice: verify the shaft fits the 6mm inner diameter and that the 12mm outer diameter suits the bore before pressing. Use a bearing driver or matching socket that contacts the outer race to avoid stressing the inner race, and check for correct endplay after fitting. Avoid forcing bearings into incorrect bores and use light grease or bearing oil as needed.

Service guidance: check bearings for noise, roughness, or play; clean with suitable solvent if dirty and relubricate with low-viscosity oil for optimal free-spin. Replace bearings that show pitting, excessive play, or overheating under normal use.