Best is to use the same sises pressure loadcapacity lists from European sites, because they are calculated with saver formula then American lists.
American TRA swiched over to this European ETRTO calculation as late as 2006 , but only for P-tires and XL/reinforced/Extraload tires ( most for normal cars used).
TRA left the calculation for C-load and up to the old calculation wich gives to high loadcapacity in the lower pressures.
Beter would be to give me the GAWR/GVWR ( gross axle/vehicle weigth rating) or beter even weighed seperate wheel or axle loads.
And maximum speed you wont go over for even a minute.
Then number of tires and axles behind ( front will be 1 axle with 2 tires )
then from tires 1. Maximum load or loadindex, 2 AT-pressure or loadrange, 3 maximum speed of tire or speedcode letter ( probably N for up to 140km/87m/h) . Can be found on sidewall.
I already googled yoru tires to be LI 115 with maximum load 2680lbs AT 89 psi with speedcode R.
So only need specifications of motorhome
will give picture of my made extra save pressure loadcapacity list in front .
used it in other forum so disrecard the highlited 119 LI and use the top line with LI 115.