grand am shakes

I just took my car to the dealer because it shakes once i hit 65mph and then get worse the faster i go. i just went to pick it up and the dealer said my tires are tucked and feathered and its causing it to shake. What does tucked and feathered mean?? their almost brand new tires...

the shaking sounds like your tires are balanced. and the feathering of the tires might be from a misalignment.