I have found so much helpfull information on this site, I feel obligated to give something back. I looked, but could not find a write up on this problem, so here is my fix for oversize tires rubbing on the fenderwell liner. This worked very well on my '05 F-250, but should work on other models as well. It is simple, clean, and FREE!
First take out the bolts at the bottom corner of the fenderwell liner, you do not have to take the liner out, just make enough room to cut. Pull the corner of the liner out and cut the outside corner of the liner off so that the liner is flexable and can be bent back like a mudflap. DO NOT
cut the liner past the pinch weld.
Next take the front bolt out of the pinch weld under the fender, but leave the back bolt in. Bend the pinch weld up and under the truck until flat (Parallel with the bottom of the Truck).
Now take and pull the liner back as hard as you can and mark where the bolt hole in the pinch weld meets the fenderwell liner. Use a drill bit the same size as the pinch weld bolt to drill a hole in the liner where you marked. Pull the liner back and put the OEM Pinch weld bolt through the liner and back into the pinch weld.
That's it, your done. You just made a couple more inches for those big mudders to move.
Simple, Clean, and FREE! I hope this information is helpfull.