I recently got my spare tire attached to the tire carrier of my Knight Customs rear bumper. I used an M4x30mm hex cap screw I got from Home Depot, drilled out a hole straight through the mount, and melted the plastic around the screw as I was pushing it into the back while getting the screw hot with my soldering iron.

It originally was set up to drill a couple holes in the body and then put an additional mount that'll clip on with a body clip to help stabilize the spare tire. However, I didn't want to have to drill into the body. I decided to try a couple magnets instead. I glued one inside the body and another one onto the outer half of the mount that clips into the spare tire carrier. The magnets seem to be holding on okay. I gave the thing a try at NJ Devils Way this morning, and the spare tire wasn't flopping around. It's obvious there's a magnet there if you look close enough. I'm not sure what I'm going to do with it yet. I gave thought to putting a smaller magnet on the outer mount, but I'd rather not mess with what I've got too much. I might just paint the visible portion of the magnet black to help it blend in. Up to this point, though, I'd say this is a successful experiment. It doesn't seem to affect the truck very much, and I've got s spare with me that I can pop on if I ever tear up a tire on fishing wire or something. I think I'm going to eventually put some stiffer springs in the back to compensate for the extra weight, but everything's okay right now.