My 20' pontoon boat trailer is a single axle setup. On the right side tire, the outside 3" is wearing out very badly, the rest of the tire is ok, and the left side trailer tire is fine too.

Been told it's probably a bent spindle.

I believe I have Carlisle tires now, and they seem to wear out so fast. I can't find Radial tires in that size. Is there a similiar sized radial I can find? I think I have 6 lug wheels, but I need to double check.