As already stated - the factory spare has a larger diameter hole to accommodate the carrier winch assembly. The factory "running" wheels (aluminum wheels) do not. If you get a flat, you're either leaving your aluminum wheel in the ditch, putting it in your back seat, or in the bed. **** poor planning from Mopar in my opinion. I guess the engineers just assume people aren't using their truck beds and will have space for a flat. Chop up the carrier if you're so inclined. I personally wouldn't do it. Several people have rigged up various gizmos to circumvent this size difference, but as often as it would realistically be a problem, I'm not dinking with it. I did opt to toss the factory spare and put a 20" steel spare with a real full-sized tire on it. If I need a spare on a truck, I need a real tire, not some Mickey Mouse BS size mismatched "temporary use only" low tread POS.