Wheel Bearing Noise
Diagnosing Wheel Bearing noise can be difficult because the sound is so similar to cupped or knobby off-road tire tread patterns. Each results in a growling noise that increases with speed. There are several ways to tell the difference.
A loose wheel bearing makes more noise while turning around a corner than a scalloped or cupped tire does. The noise is worse on the side with the bad bearing. Good wheel bearings allow the wheel to spin smoothly, but also keep the tire running true.
Wheel Bearing Diagnosis
Overinflate the tire associated with the noise a few pounds and see if the noise changes. If it does, move the tire to another position and test drive the vehicle to verify suspicions. Special listening devices amplify the noise created by a worn bearing, making it easy to distinguish it from other components. During the initial inspection, grasp the tire at the top and bottom and rock it back and forth. There should be no movement with sealed bearings and very little with tapered bearings.