Easiest way is to use the chalk line across the tires to find optimum PSI. Google it. Short version, take common blackboard chalk and make a couple heavy lines across the tires(all 4). At unloaded weight, you may find 50-55 psi is good for the front, 40-45 for the rear, the chalk will wear off evenly across the tire after 1/4 mile of straight rolling. Walmart parking lot on a dry sunday morning works well. If outside is gone, pressures, too low, if the middle is gone, too high pressure. Unloaded I used to run 52 front, 45 rear. Loaded 60 front, 70 rear.
