We recently bought a used RX350 from the dealer sold with a brand new set of Goodyear 18" Eagles. The car has been aligned and the alignment has been re-checked. The car does not track particularly well...mostly to the right but sometimes to the left on grooved pavement. Any body know how to determine if a tire has a bad belt? Any body have opinions on this tire? What is expected tire mileage (life) for this RX350? Anybody have experience with the 18" Yokohamas?