I first considered a tank/compressor system. There is just no room under a JK for a tank. I went with CO2 because I can also use it for air tools on the trail and for welding in the garage - multi-use system. I mounted my tank on the driver side in the back of the Jeep on drivers side - it blocks access to the tool tray cover, but then I rarely get in there as all my trail stuff is in my boonie box. Sure makes airing up a breeze! 35 seconds per tire to go from 12 lb to 32 lb and I get up to 7 air ups per tank.