You can use my multilingual MotorhomeRV-tire-pressure-calculator, wich can be found in next map on my One-drive ( former skydrive) that belongs to my hotmail adress with same username as in this forum ( so combine yourselves if you want to contact me by mail, spamm machines cant)
First download the american version ( tire instead of tyre) to your computer by RIGHTCLICKING
and then choose Download
from the dropdownbox.
Other means go wrong like leftclicking or choosing open in Web-app or Excell.
After download and eventual virus check ( you never know what those Dutch put in to it) open it in Excel programm on your computer. But Open Office CALC can handle it too.
The calculator calculates the needed pressure with my own formula wich is better then the American used formula and even better then the European one wich I once got hold of and my tire pressure story began with.
It also takes a reserve for overloading and unequall loading, and shows what is used and the reserves , but you can chanche it to your own ideas.
So if real seperate wheel weights are known , use part 3 for it . if only GAWR's are known it uses that in part 2 .
Also usefull information about loads and reserves, so you dont have to calculate that yourselfes.
It calculates same pressure R/L because car- and tire-makers advice that.
But using different R/L per axle is not that bad to my opinion.
Reasons for same pressure could be , that the mass on an axle gives same sideward forces on Right and left wheel so sideward stifnes of tire should be the same.
Mayby something in the middle would be best.
If you cant work with my calculator , give the weighs ( weighed or GAWR's) and the exact tire data ( maximum load or loadindex, Loadkind ( C to H -load) or AT-pressure ( reference-pressure, wich is not the maximum pressure) and the maximum speed of tire( mostly N speedrated is max speed of tire 140km/87m/h) )