Originally Posted by clearprop75r
... it says on the tire to run them @ 80PSI.
no they don't.
Sure. Start from scratch (with good new tires).
And assume that Winnie didn't know in 1982 what a good radial tire would be able to do in 2010.
1) Accurate weight at each corner and axle of the coach.
eg: 14,000lb Coach = 9,000 rear (/4) + 5 ,000lb front (/2)
2) Read the MAXIMUM weight at Xpsi on the tire wall.
eg: 3600lbs dual @95psi (and) 3400lbs single @95psi
3) Do the math.
Rear: 9,000 / 14,400 (3600x4) =62.5% (x95psi) = 59psi
Frnt: 5,000 / 6,800 (3400x2) =73.5% (x95psi) = 69psi
This you get the MINIMUM air pressure required for good condition NEW tires to support the KNOWN load.
Cheaper, older and/or worn tires become a crapshoot.
Hope that helps.