Cupped Tire Symptoms
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.
Both cupped tires and bad wheel bearings cause a similar growling noise while driving. This problem can make it difficult to distinguish between the two in operation.
Bad struts and shocks cause cupped tires. They're 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 coil from oscillating. Perform a jounce test to verify a bad shock. After pushing down on the bumper, it should return to normal and not continue to move up and down.
A worn wheel bearing causes a growling sound in operation. The wheel on the outside of a turn with the vehicle's 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.