I'm the OP. Our rig is a 2014 Nexus Viper 29V, 30' class c on a 2013 E450. Our rear axle weighed 9960 lbs on the scales packed for a weekend trip, full gas, 10gal fresh water, empty dump tanks. My tires are Michelin LTX m/s2 LT225/75R16/E 115 rated for 2470 @80psi (max psi) each on the rear duallys--I'm 80lbs overweight on the tires--not the axle spec. I have also had 2 leaves added to the rear spring pack to raise the rear and and increase the carrying capacity of the springs.
I can't use a wider tire because the offset is not enough and the duallys would rub. I have ordered Hankook F19 7.50R16LT which is very slightly narrower than my 225's and is a load range G tire at 100psi. At 90psi duals are rated at 2630lbs/tire which is 10520lbs for the axle--which I will not need--as ksg5000 mentions, I would use the load/inflation table for the F19.
The Accuride catalog sez--the 16x6 light truck wheel is rated at 80psi max. I have looked at the outside dual, and the front wheel and nothing that resembles a "Max psi" is stamped on the wheel. My local Ford parts guy could not find anything is his computer which had that spec either. I have requested that info from Ford CS last week, but no reply yet.
You'all are correct for the tires installed, the psi on the sticker is correct. Others on this and other forums have installed 17.5" tires to get safer margins--I choose to give these Hankooks a try. If you notice on the RV section of Michelin tires--the LTX tires is not even listed. The only 16" tire listed is the XPS Rib which is a steel belted tire, vs the LTX fabric belted.
Thanks for all the replies,
Ron