To the OP. If you're referring to what pressure to run unloaded, take you truck to a scale and weigh each axle. Then use Nexen tire load chart to determine the correct pressure for the load the tire is carrying. Do the same if you carry a load.
Many tire manufacturers will state that the pressure listed on the tire sidewall is only for the maximum load the tire is designed to carry. And is not a recommenced tire pressure setting for your vehicle that may have varying load conditions.
One poster mentioned that he runs the sidewall listed pressure all the time and is willing to sacrifice comfort for safety. Wrong. Wrong. Quite the contrary. When running 80 psi on a light truck dully that is unloaded, you compromise the tires traction ability in both braking an acceleration.
ryoung