A wheel bearing is a set of steel balls held together by a metal ring called a race. They help wheels spin fast with as little friction as possible.
Wheel bearings allow your wheels to spin freely. Sealed bearings can last up to 85,000 to 100,000 miles.
If you don’t replace a damaged wheel bearing before it fails completely, the wheel will completely seize up. and then safety becomes a big concern. It is best to replace bearings in pairs.