This bearing supports the planetary-gear set inside the rear wheel hub reduction. It carries the radial and axial loads transmitted from the final drive to the wheel hub. A worn bearing produces audible rumble and increased hub-end play, which can misalign the planetary gears and accelerate tooth wear. The original-spec raceway geometry and internal clearance match the housing bore and shaft journal of the reduction assembly, so no shimming or adapter sleeves are required during replacement. On installation, clean the housing cavity and apply the specified grease; torque the hub-retaining nut to the manufacturer's value.