Check this and it is cheap and easy. Check to make sure the wheels are true, you might have a bent wheel.The machine will show the wheel balanced, but it wont check for "wobble". This happened to me once. New vehicle with low miles, the wheels were computer balanced yet there was a vibration that set in about 50 and went away at about 65.The mechanic finally raised the suspected wheel and did an "on vehicle wheel spin up." He got that wheel to going good. The machine showed that the wheel was balanced, yet the fender was shaking, the mirror was rattling...He checked the wheel and it was "out of true". A new wheel solved the problem. The dealer suspected that someone banged a curb or something before I received the vehicle. It happens.