Bruce

Larry,
I had the same problem once when I tried to take the spare off. It was caused by bottoming out the spare at some point which bent the bar that holds on the spare. The cover on the spare was badly scraped on the bottom so this is what I surmised.
The larger trailers do bottom out quite easily.
Maybe you should install a lift kit.
I mounted some wheels on the bumper which are supposed to prevent bottoming out.

Bruce