Tires: abnormal wire, alignment problem, rear tires

Question
I have a 2003 30 ft Wildcat Fifth wheel. The back tires wear abnormally on the outside. The outermost tread are chopped unevenly. I replaced the tires with Goodyear ST D rated tires and had them balanced. After a 4500 mile trip, they are doing it again. The back passenger tire outermost thread is worn to the core. I can not afford to replace the two back tires after every trip. I stopped by the Wildcat dealer for help. They do not deal with tire problems.  If anyone has a cure for these problem please let me know. I can seen pictures if it would help.
Thanks,
Lenwood

Answer
You probably have an alignment problem, so that ought to be something the Wildcat dealer ought to be able to advise how to fix or at least where to go to get the alignment looked at.

The other thing you ought to look at is the level of the trailer.  If the trailer is tilted forward, the rear tires would be dragged sideways everytime you turned, instead of both tires working together.