https://www.f150online.com/forums/sh...threadid=23070

Some ideas from a few guys a year or so back to prevent the side wall marking. I'm not sure how much moisture might be retained in a piece of carpeting, enough to encourage rust??

Sorry, I don't have the picture of my solution anymore. Maybe you can figure it out from the description. chuckw

 

I'll have to think about the carpet vs. other ideas, but I will come up with a way to stop this from happening again.

I've also had some time to think about this and I have concluded that the frame wax is the problem. There is just no way that firm rubber to metal contact could cause this much damage in only 4000 miles of driving. Also, if rubbing friction caused the damage, why is an intact piece of the sidewall stuck to the frame? Friction did not cause this. It is some type of bad chemical reaction. What could cause this is 14 months of the tire sidewall being in contact with an oily substance that degrades rubber.

I will be taking pictures of the tire and the rubber that attached itself to the frame this weekend. I think I should submit this pictures to Ford and also to NHTSA. I believe this is a safety issue and that all F-150 spares should be checked for this problem. Any truck that has the frame wax on it will kill the spare if not modifed. I don't know what Ford was thinking when they designed this system and then covered it in frame wax, but it was a huge mistake.