Just my two cents, but I 100% agree with between 10-15 lbs air pressure and just using plain old radial street tires, preferably balding, because they bag out real nice and create more surface area. I also have the 27" Khumo M/T's on my 80 lifted wagon, they did ok in the sand but I almost cried when a mid 80's toyota van 4wd made it up a hill called V8, down in coosbay, and I could only make it halfway. I'm certainly sure it's because the M/T's dig in too much.