On the 21" haulers mounted on 8" wide rims I started with 67" rollout ,after the 22psi stretch in the sun for two days I am at 71 roll out,I would like to get a little more if possible.I have a buddy that has some of the hard to find 7" wide rims.I was told thats good for another 2" of so I might give them a try.Man I thought the tires were going to bust when I added the 22 psi, 30psi would probably have me shittin in my pants .lol My buddy at the tire center said i could do 25# easy :shrug: