I would be more concerned about my front end holding up with a tire like this. Big and WIDE are generally not a good idea for our IFS setup and you may very well end up in teh shop instead of on the trail. KenP was running a 38x15.50 18 and i think he was only able to wheel for a day or two due to front end issues(centerlink and bent fabtech tie rods i believe). You can search but im thinking you would be better off with a skinny tires with less offset to minimize the front end stress.
That being said KenP also sat his truck after driving hundreds of miles to tellico due to a "bent" tie rod that you could not even tell was "bent". RuggedH2 runs i believe a 38x15.50 KM2(but with a Rancho 4in) and wheels the crap out of his rig so he would probably be my go to as far as tire advice. PhilD on teh hummer*club would also be able to shoot you straight.
A set of 39.5 x13.50 Iroks would suit you just fine im thinking
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