My good buddy has a 1966 Corvair and has some over 55 mph vibration issues. He has 14" OLD style Crager wheels with 205/70 14 BFG TA Radials. This is the second set of new tires he has purchased in less than a month hoping to alleviate his issue with no luck. Tire installer sold him on the second set of more expensive tires thinking that was the problem but it was not. Any ideas??