I GOT A ULTRA LX COMP (NEW DESIGN) MADE BY OFNA, AND MY PROBLEM IS THAT EVERYTIME I GET A NEW SET OF TIRES, THE MIDDLE OF THEM GOES BALD, MORE SO IN THE FRONT. I RUN ON DIRT, GRASS, PAVEMENT, ALMOST ALL OF THE THINGS THAT YOU WOULD FIND IN A VALLEY. ANY IDEAS? THANKS!