Some of you guys with later model rigs may have already done this exercise. I'm going to try to get coach weighed in a few days and get tire pressure optimum, and I'm working with a dash of "Cowboy Logic" here in the mean time:
Tires Goodyear G670 275/70R22.5(H)
GVWR 31,000 lb
Front GAWR 12,000 lb
Rear GAWR 19,000 lb
Dry weight of my coach is 25179, does not affect calculations below:
So, assuming I load up and am near the axle weights above, and assuming a balanced left to right load, and using the Goodyear loading/inflation chart: http://www.goodyearrvtires.com/pdfs/rv_inflation.pdf
Then a minimum inflation of 90psi in the rear (each corner at 9500/2 = 4750 per tire) and 105psi in the front (6000 per tire) would cover me as per the chart, correct?
Then assuming a 5% variance from max axle weight side to side would make the front corners (instead of about 6000lb each) 5700 and 6300 and the rear corners (instead of 9500 each) 9025 and 9975 requiring a min of 110psi on the fronts (working off the heavier corner) and still require just over 90psi for the rears (9975/2 = 4987.5# vs. chart of 4980)
SO, even if I wanted to run up to 5psi over, assuming I wasn't seriously unbalanced side to side or overloaded on either axle, and if my exact rig weight was unknown, wouldn't 110 to 115 in the front and about 95 psi in the back be a good "safe zone?"
More to the point, have any of you found any situation in your setups with these tires that would make you want to put 100+psi to the rears?