[Blazer1970]

Those tires have a very high load rating for the weight rating of the truck. At 80 psi you will wear out the center of the tread very quickly. Also, the ride will be very harsh. I would always run the fronts at 45 psi. If the truck is run mostly unloaded I would run the rears at 40 psi or so. Only increase the pressure in the rear tires if you have a substantial load in the bed. The maximum pressure rating on the side of the tiire is intended for the maximum load rating of the tire. If you were to weigh the front and rear of the truck you should run the tires somwhere around the same percentage of maximum pressure as the percentage of maximum load that you are putting on them. The door sticker on that half ton truck probably calls for a tire with a "C" load rating.