Have you had the alignment checked on all four wheels? Other possibility is
that it's a wheel bearing or CV joint that's going. Same noise when in
neutral and coasting? Any different on a right or left turn?

Who changed the winter to summer tires? Loose lugnuts?

"somebody" > wrote in message
...
> We have a 1998 SL2 with 105,000 miles. We put snow tires on it last
> fall for our kid's year at college. Now it's back and has summer
> tires on it.
>
> But now it sounds like there are coarse tread tires, it rumbles, with
> pitch going up as speed goes up. Any ideas? It is loud enough to
> need earplugs at highway speeds.
>
> Thanks!
>