I have roughly 20K miles on a set of Goodrich Touring T/A v-rated tires that have been balanced and rotated every 8K miles. Tire wear is also even, with the exception of slight ridges (I think Haynes calls it "cupped") on the inside and outside of the rear tires only. Problem is, the tires have now become quite noisy at 30-50 mph. Although there is no vibration and I just had them rebalanced, they sound as if they are out of balance- you may know the sound. I am at a loss as to what this could be- there may be internal damage in one of the tires (belts misaligned or something). Suspension is in reasonably good shape for an 8 year old car. Thanks in advance for any advice.