I have a drive on trailer for an 18ft boat. The<br /> problem is it seems to pull hard and when I get back from the lake which is about 8 or 10 miles the tires are pretty warm. I checked rim to rim in front and behind the axle and it looks like it's off 3/4 of an inch.When I check from back of boat frame to axle on each side it's about the same. There is a spare tire on the trailer and it is dipped out on the sides of the tread (inside worst). And nothing looks bent. Any ideas ???