some what confused here I weigh my camper and the steer axle weigh was 4320 lbs do I take the 4320 and divide it by 2 and then look up that weigh on the tire chart to see how much air I need in my ste...
I'm assuming your motorhome is on an E450 chassis, judging by the size listed in your profile. If so, don't overthink it and follow the manufacturer's tire inflation sticker on the door post. 65 psi front, 80 in the rear should be very close to optimal pressure. The tire inflation tables are great for when you're running a lower weight than max GVWR, but a larger class C motorhome is going to be fairly close to max weights.