This happened yesterday while out on the interstate. I don't know how except maybe the tread started to come off and caught the fender. I did notice a flat spot about the size of a quarter an inch inside the tread area a couple of days ago. Maybe it had something to do with my new brake controller?I don't think I ever locked up the brakes though. What's the deal with trailer tires anyway? Can't reguler truck tires be used? Somebody in the know please edumacate me. Tony By the way, my bulldog pipe mount worked perfectly.