I posted this a few months ago! I've since talked to the guys at the Ford truck center. They recommend running the tires at 110 psi, because that's what Thor has on the placard? When I took my rig in for service, they inflated the tires to 110 psi.
So, Michelin publishes a psi table, while Thor recommends placards the PSI, based on the max weight of the vehicle!
Posted a few months ago:
Those 22.5's are nice! Michelin has a tire chart specifically for these tires. Weigh your rig fully loaded, as you are heading out for a road trip. Check the tire inflation table and adjust your psi accordingly! Thor recommends running the tires at 90 PSI, you will find that weight on the placard by the drivers seat. That pressure is based on the vehicles max gross weight of 22,000 lbs.
My rig fully loaded for a trip weighs in around 20,800 lbs. according to the Michelin chart, they recommend I run my tires around 77-78 psi. That 12 psi made a big difference in handing.
I also invested in the TireMinder system, what a life saver! Had an inside dual valve stem fail while driving at highway speed. The system warned me immediately, I was able to pull off to a wide spot and inspect it. (There was no change in handling with the inside dual flat!) Found a Les Schwab shop 10 miles away, they told me to drive it on in!
After a 30 minute repair I was on my way! Without the TireMinder, I could have easily driven another couple hundred miles before noticing a problem. By then it could have been an $800-1,000 dollar repair vs a $28 dollar repair!!
On that one instance, the TireMinder paid for itself!!
To me it was well worth the investment!!
Hope this helps!!