But the thing is that the mfgr's recommended pressures are assuming that, among other things,
A) The vehicle is running the specified diameter, width, height & type of tires AND rims
B) That the suspension & drive train contains factory-spec'd parts (shocks, springs, differentials etc) and has not been altered (dropped, raised, widened, changed gear ratios etc)
C) The vehicle will be used for it's intended uses & loads, and at normal speeds too
If any of the above have been changed, then the pressures should be adjusted accordingly, and based on the tire mfgr recommendations
On my 011 Expy EL, I run 37 no load or 45 loaded, but I don't tow anything or carry extra heavy loads, only some lumber, landscape supplies, furniture, and the Fam...