GOOOO

My A4 was making a very faint noise when moving--can be described as rolling a marble inside a plastic tennis ball container. Anyway, I took the tech out for a spin and he heard it. He mentioned that it might be dried out bushings. When I picked up my car, he said the bushings were fine and the reason for the sound is that my tires are "cupped". What the "H-E-Double-Hockey-Sticks" does that mean? He said he put the car on a rack and could see it? My car only has 13,000 miles and he's telling me that driving on uneven road surfaces have caused my tires to become off-balance and "cupped"?

WJM

the produces an uneven/cupped effect on your tires. imagine little bald spots.
look at your tires and you will know if he is FOS or not

Trey R

Not sure how cupped tires would make the noise that you're describing, but they could be responsible for a rough, wobbly, out-of-balance kind of ride.

Your tires can become cupped if they are out of balance or your suspension becomes very worn - doubt you've got a worn suspension after 13K miles. Basically the tire tends to oscillate vertically, causing a severe wear pattern to form in places on the tire, literally causing concavities in the tread. Their formation would make the balance worse, leading to worse cupping - viscious circle.

Hope my explanation is understandable and technically correct. Apologies if not.

Glenn R

Mine was caused by driving around without enough air in the tires.

Auditude

The toe-in was way out of spec but by the time I realized it it was too late. The truck vibrated very badly and I could no longer balance the wheels. You could see the cupping in the tread which was very obvious. I had to replace the tires. They had less than 12K miles on them.