you can fit almost anything up to a 35x12.5 tire on the stock rim... just pick one you want

I've seen someone posted on here with mud grappler 35x12.5s on the stock 18"s with just a leveling kit... may have to do the pinch weld mod if you get them though, because their sidebites are 15mm sticking out... I've seen someone post they're the widest 12.5" tire because of that...