Quote:
Originally Posted by Dippytwo
I’m sure this has been covered before, but I want to make sure I’m running the correct pressure in my tires. I have the Goodyear 245/70R 19.5 with max pressure 110 psi. My Thor sticker says to run at 82 psi (all tires), the RV shop that I got my CHF done at says to run at 110 psi since that’s the max load on the tires. I took my MH to a CAT scale, the front axle is 6020 lb, rear axle 9770 lb, (total 15790 lb). I looked at that Goodyear chart and not sure if I’m reading it right, the best I can figure out is they are telling me to run at 110 psi. So, 82 psi or 110 psi?
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Call myself "Pigheaded Dutch Selfdeclared Tirepressure-specialist" nowadays, and story began when I got hold of the official European calculation and went running with it, got much wiser in time, and google dayly for tire/tyre-pressure to see if I can help ( or ventilate my ideas).
Made a multilingual motorhome-tirepressure-calculator with excell , and filled your data.
First looked at the link given of Goodyear to determine the maximum load of your tires.
Was the G-load/LRG version of the list, and 4540lbs Single and 4410 lbs Dual per tire AT 110 psi. this I searched back to be Loadindex 133/132 wich is stange because mostly dual 2 lower then Single, and then even in American system sometimes 4 LI steps lower for dual.
so adjusted it Dual to LI 131 / 4300 lbs maxload.
Then filled in in my made calculator wich first adds 10% reserve to the weighed loads and then calculates the pressure with my own determined extra save formula ( even gives higher pressure then the European formula, wich on its turn is saver then the American calculation.
This allows to go verry low in the pressure with still the same deflection of tire as when maximum load AT AT-pressure on tire, wich is the goal of all calculations.
Gave advice of
Front ( single load axle) of 79 psi ( make it 80 psi) and Rear (dual-axle so 4 tires on the axle) of 67 psi ( make it 70 psi).
But how did you weigh, was it with all the persons and things in the motorhome, so as you use it in practice, or empty , or some persons not inside, or minimal water or fuel in tanks. Then you shoud estimate what comes to that "empty " weight , and I can help you with that too, but the outcome will be less acurate, as when weighed fully loaded .
Then these advice pressure would be to low, so still possible damage to tires by overheating.
Greatings from the Netherlands
( ja dat is) Peter
Thor Forums
