This is the best choice for any spare tire mounted bike rack. It will carry 2 bikes easily, and the bike arms will fold down when not in use. The slickest feature of this rack is that it will accommodate a spare tire that is not mounted on the center of the vehicle. This will ensure that your bikes don't stick out further off the side of your car than your side-view mirrors, preventing you from accidentally hitting them when squeezing through tight spaces.
Check to make sure this rack works on your vehicle. You will need to remove your spare tire to mount this rack.
Advantage of using this rack over a strap-style spare tire rack, is that this rack does not entirely depend on tire inflation of the spare tire to work, as opposed to a cable/strap style rack; So, if you get a flat tire on your jeep, your bike rack will still work.