Originally Posted by cgocifer
It "sounds" like a shimmy or wobble, but doesn't feel like anything. Know what I mean? It isn't a steady hummmmmm, it is an unsteady, well, wobble sound. It sounds like the car should be shaking, but it doesn't.
It might just be road noise. Some tires get louder as the tread wears down. Is it all the tires or just one? When you said a shimmy or a wobble I was thinking maybe damaged belt in the tire, but if there's no physical shaking or wobble I'd check for what SVO said.