Carbone, you's get more accurate answers if you'd post the tire size & load range. AZ Kid's answer is good _if_ yiou have load range E's. To use any tire maker's load-pressure chart, you need at least actual axle weights. Corner weights are even better.
Jim, "Windows message: Your drive C: is about to explode. Get out of the building, now! (This is not our fault, honest.)"
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory')