Cupped Tire Wear

A cupped tire.

Worn or damaged suspension components like bad struts and shocks result in cupped tires. They are responsible for preventing the tire from bouncing up and down after hitting a bump in the road. The damping effect of the shock prevents the suspension coil from oscillating.

Hub and Bearing

Cupped tires and bad wheel bearings make a similar growling noise while driving. This problem can make it difficult to distinguish between the two in operation.

Cupped tires vs wheel bearing diagnosis.

A cupped tire changes its pitch from one surface to another. This change in pitch is true with all tires but much more pronounced with a cupped or scalloped tire.

A shock bounce test.

Perform a jounce test to verify a bad shock. Be careful not to damage the bumper. After pushing down, the bumper should return to normal and not continue to bounce.

Wheel Bearing Noise

A worn wheel bearing causes a growling sound in operation. The outside wheel of a turn with the vehicle's inertia and weight leaning on it will be loudest. A bad right front bearing will be loudest while turning left. Raise the vehicle and grab the tire at the top and bottom. Rock it back and forth feeling for looseness; there should be little play, if any.