How do you know if rear wheel bearing is bad?

A bad rear wheel bearing can be identified by several signs, including a grinding or humming noise coming from the rear of the vehicle that increases with speed, or a noticeable vibration while driving. You may also notice uneven tire wear or play in the wheel when it's jacked up and wiggled. If there is any visible damage or rust on the bearing, or if you feel a roughness when spinning the wheel by hand, these can also indicate a failing bearing.