My suspension consists of GC Koni D/A coilovers with Eibach springs, Racing Dynamics front and rear sway bars, and Kuhmo MX 255F/275R 17's.

I have 30k miles on the '02 M Coupe.

The thumping noise started two weeks ago. It's caused by the RIGHT REAR tire only. Whenever the tire goes over any uneven surfaces, I feel and hear thumping sounds.

It's not metal to metal, in fact it sounds like the surface that it is hitting might have rubber or padding material on it.

On smooth freeway surfaces, there is no sound. On uneven freeway surfaces it comes out quite a bit, as the suspension oscillates. On city streets, it comes out the loudest and most often.

It doesn't seem to affect the car's handling at all. My mechanic took the car out on two separate occasions and checked the suspension thoroughly, and determined that the shocks and the RSM are fine, but so far he can only guess at what it might be.

I am hoping to gain some insight from the gurus. Please help. TIA