spent years trying to figure out vibration....thinking it was part of the vehicle. ended up after many years of tire balancing....changed out the tires and had a particular shop put the correct weights on the tires. had alignment checked almost as many times as we've had the balancing done. it was the tires that came with vehicle and poor balancing done by various mechanics...who put weights on top of weights just to fling off again after half a mile of driving....just when we were thinking it was driving much better...just to feel the same vibration shortly after the thought.