What is the difference between interference fit and clearance fit for bearings?

Interference fit (press fit) is used when the bearing ring rotates relative to the load direction - inner ring to shaft when shaft rotates, outer ring to housing when housing rotates. This prevents creep (relative movement) between ring and mating part. Clearance fit is used for the stationary ring, allowing easy assembly and accommodating thermal expansion. Improper fits cause ring creep, fretting corrosion, or bearing damage.