1991 Chevrolet Corvette

I had 4 brand new Mickey Thompson Street Comp tires (2 of P275/40R17 for the front and 2 of P315/35R17 for the rear) mounted on factory rims and spun balanced by my local garage. I then mounted those tire/wheel combinations onto the vehicle. I then drove the vehicle to the same garage for a yearly state inspection, and on my way there the steering wheel shimmied half of the time. When I got there I checked the lug nuts for any looseness with a torque wrench. All lug nuts were accurate. After the inspection I drove the car back to my garage (under 25 miles round trip) and removed all 4 tire/wheel combos, loaded them into my truck and brought them back to the garage to drop them off to have them balance checked in between the mechanics other jobs ahead of me. The mechanic checked them and informed me that all 4 were balanced accurately, as a matter of fact, he did them in front of me so I could see. He recommended that I take them to a shop that has a "Road Force Balancer". I found such a shop and after they tested all 4 tires, in front of me, they indicated that the 2 front could not be balanced, that they were "out-of-round" beyond balancing. One rear combo was passable and the other was just barely out of reach, but could possibly be used. It may even out after so many miles. I asked him if the rims could be the problem and he indicated to me that the machine he uses also measures the wheel itself, and he showed me how it does it. All 4 rims measured true. Thank you

TL* THE CONTACT OWNS A 1991 CHEVROLET CORVETTE WITH GOODYEAR EAGLE F1 ALL SEASON TIRES, SIZE 275/40ZR17 , DOT NUMBER: MKX26FHR10007. THE CONTACT STATED THAT ALL FOUR VALVE STEMS FRACTURED WHILE DRIVING OVER 5 MPH. AN AUTHORIZED GOODYEAR DEALER DIAGNOSED THAT THE VALVE STEMS WERE DEFECTIVE AND WOULD NEED REPLACING. THE FAILURE WAS NOT REPAIRED. THE FAILURE MILEAGE WAS 53,000 AND THE VIN WAS NOT AVAILABLE.