New tires on 2007 tahoe in feb2010 tires are wearing on the inside on both front tires, I put the front on back and vis versa front tires are wearing on inside again bad!!! I have had car lined up at two different Chevrolet dealers both said they were not out of alignment usually use Michelin but these are Bridgestone Towing bar is level from coach to car any suggestions? They have 16000 miles on tires 10000 was towing. Thanks Gary