Stewart here is the chart look at the lowest tire listed 235/80/17. Your rear axle weighs 6,740# divided by 4 is 1,685# so using the chart under dual wheel 1,725# is the closest on the chart @ 40psi, Now add 5psi per GY Tech Support recommendations. Bottom line proper inflation for your 4 rear tires is 45psi ea.
Now for the front's 5,6430# load divided by two 2,730#. Chart says for single wheel application closest weight is 2,815# @ 70psi. Adding 5 psi is 75 but there is edge wear to consider so add 5psi more for a total of 80psi fronts ALL the time.
I have used this method for at least 1 million miles with perfect tread wear, stopping contact patch and ride quality.
Also get that front end aligned NOW!!! I can guarantee you will start seeing outside front tire stepping if you don't. Disregard RAM's spec of 1/4" toe and set to 1/64". ONLY rotate front tires side to side leaving the ROTATION the same. Leave the wheels in same location. Do this once every 15k.
As you can see 35psi rear unloaded is MORE than enough carrying capacity at 6,280#.
FYI the MAX inflation of 80psi will net you a total of 11,340# of carrying capacity on the 4 rear tires!
diesel shadow looks like the 80psi part of your chart is off, 35 is correct did not check other numbers.
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