Taking blanket numbers like the max PSI on the sidewalls {which by the way is merely a statement of fact not an instruction to do so}, or the numbers posted inside the drivers door will often lead to bad results. Your tires should always be inflated to the proper psi for the load they are actually carrying.
The chances that those fixed numbers which can not/do not take into consideration what loads are actually present have little chance of being correct. {Yep, even a broken clock is right twice a day .... but I digress...}
Don't know what sort of rig you have but a trip to the local CAT scale is in order. I run my 24' Class C with E rated Michelin LTX M/S 2's at 60 on the fronts and 65 on the rears as this is the proper psi for the weight they are carrying. The ride is very smooth even with the heavy duty Bilsteins I run. If I inflated all 6 to the 80 psi max the ride would be insanely rough and the tires would wear out prematurely.
As always.... Opinions and YMMV.
:C
