I have a theory. Considering that there are different load ratings and weighted trucks my rule of thumb is to air down till the side wall buldges a bit.

My reasoning for not really speaking in PSI is because with a set of D load tires you will need to air down much more than the same tire with a C load rating. The sidewalls are much stiffer and require more air to be removed to gain the same results.

My two little copper coated metal pieces that cost more to produce than they are worth....

Joe

A gun in the hand is better than a cop on the phone.

98 Passport 33's, Supercharged, Calmini Bumper, rockbars, diff drops, Teralows, 4.77's, Aussie and ARB lockers, Safari snorkel, Optima red top.