[thstone]

I assume you mean the front wheel bearings.

I've replaced all my wheel bearings at least twice (I think I'm on my third set in the rear). Racing with stiff suspension and sticky r-compound tires is really hard on stock wheel bearings.

They will typically make a low growling or humming sound - especially around a corner of the opposite direction (left wheel bearing hums on a right hand turn since the outside tire gets most of the load).

The noise typically gets steadily worse over a few weeks (or months depending on how many miles you drive) so eventually it will be really easy to hear if that is the problem.