are you locked up in the rear?If not Iwould just run the same size gears and air down.seems if you have different size gears if you spin tires it would pich in a funny direction.My buddy bought a blazer,it had different gears.took it in the mud and the back would track around the frond.went through the feilds sideways.I drove my runner with 25psi on the icy roads and open diff with no problem for years in montana back and fouth from missoula and kalispell.did really well with nonstudded and siped tires..
