Tamiya AO-1011 620 Ball Bearings (2 pcs.)(94389)

A pair of 620-size ball bearings for Mini 4WD roller units, approved under Tamiya's official Mini 4WD competition regulations. Each bearing measures 6mm outer diameter, 2mm inner diameter and 2.5mm thick, sized for smaller-diameter roller setups.

620 is the smaller of the two ball-bearing sizes Tamiya sells individually for roller maintenance, the other being the larger 830-size bearing (AO-1008), intended for bigger-diameter roller units. Many of Tamiya's smaller aluminium ball-race roller sets ship from the factory with a 620 bearing already pressed into the roller, so this two-pack lets racers replace a bearing that has become gritty or seized from years of use without buying an entirely new roller set. A well-maintained ball bearing spins far more freely against a course's guide rails than a worn one, which directly affects how much speed a car scrubs off every time it brushes a fence.

• Contents: 2x 620 ball bearings
• Dimensions: 6mm OD x 2mm ID x 2.5mm thick
• Competition-legal under Tamiya's official Mini 4WD rules