Are they breaking when the wheels are straight and spinning or when they are turned and tourque is applied , i would think it`s shock load from to big a tire ?? Is anyone else having this trouble . Mine has stock wheels on it and iv`e talked to a few techs and they sugest no bigger an 27`s should be put on. Just a thought . Not a good idea to run two diffrent tires frt and rear because there not going to be the same circumfrence, and diffrent traction frt and rear is hard on the trans.