What is the max safe cold tire pressure?

[thomseninc]

At the MOC rally I had my F-250 and 3231CK weighed by the RVSEF crew. I was told the tires on the rear axle of the F-250 were underinflated for the load they were carrying. I have been inflating them to the max cold number on the yellow placard in the door jam (65 psi), but was told (err, suggested) that they be inflated to 80 psi. When I got home I asked the Ford dealer truck guys their opinion on if it was safe to run the rears at 15 psi over the number on the sidewall and they suggested I ask the Michelin guys for guidance. I called Michelin and spoke with their tech guys. They suggested I ask Ford (when did all of the tech guys turn into lawyers?) So, I’m going to ask my MOC friends for your opinion (no lawyers need respond): run at 65 psi ( 3195 lb load rated vs 3600 lb measured), or run at 80 psi (enough load capacity, but 15 psi over the sidewall number)? Or split the difference (72-73). FWIW, I have put around 5K miles on the rig with the rears at 65 psi.