ravenstown

My first time posting but have been reading through the forums. I have a 2015 chevy silverado 1500 LTZ Z71. I bought it brand new last September with 14 miles on it. The first day driving home I could feel a strong vibration and could see see the steering wheel vibrate and the passenger seat shaking and of course felt it in the driver seat. 1 year later with 12,000 miles on it I have been to the dealer 3 times and each time they road force balance. I have only been there 3 times because I do not drive the truck much. I had an outside mechanic look at the truck and he said all 4 tire are cupping which should not be happening. I called my dealer and the service manager said the he and two other techs did not see any cupping on the tires and the vibration was gone after the last road force balance. I have an appointment there tomorrow to have it checked out again. He said if it is the tires, due to normal wear, they are not covered. the truck has 12,800 miles on it and vibration issues documented since day one.