Yokomo BB-126-2 6x12x4mm Ball Bearing (2 pcs.) R/C replacement bearing  [BB-126-2]

Compact 6x12x4mm ball bearings

This item is an R/C-scale accessory supplied as 2 pcs of 6x12x4mm ball bearings intended for general bearing replacement and maintenance in radio‑controlled models. The listing matches the BB-126-2 designation and provides the dimensional reference used when checking fit for hubs, carriers, or other bearing seats.

When replacing bearings, confirm the bore, outer diameter, and width of the receiving seat to ensure the 6x12x4mm size matches. Bearings of this size are commonly used where a low-profile 4mm width is required; measure the housing before installation to avoid interference with seals, spacers, or nearby components.

For installation, use gentle, even pressure and appropriate tools to avoid cocking the bearing during press-fit. Check that rotating parts spin freely after fitment and that any retaining clips or seals are correctly positioned. In tuning contexts, bearing condition affects drivetrain smoothness and motor load, so replacing worn 6x12x4mm bearings can reduce friction and improve component responsiveness.