In my dually, i run 80 in the front and 50 in the rear untill i get ready to put a load on it, then i pump the rears up according to how much load i am putting on the rear axle. If i am hauling 4k lbs in the bed, i'll pump em up to 80 but if i only have 2k lbs in the bed, i'll run 65 in them.