Forum Discussion

Explorer

Aug 13, 2018

Tire Pressure Questions on my Michelin XRV 255/80R22.5

I was wondering the proper way to calculate proper tire inflation based on the manufacturer's ratings.

I currently have the Michelin XRV 255/80R22.5

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BELOW IS THE MANUFACTURERS SPECS
Per the Michelin website
Max Load Per Tire Single 5205/110 lbs/psi
Max Load Per Tire Dual 4805/110 lbs/psi

Loads per Axle End

PSI SINGLE,lbs DUAL,lbs
75psi 4070 7410
80psi 4300 7720
85psi 4440 8080
90psi 4620 8410
95psi 4805 8820
100psi 4975 9050
105psi 5150 9370
110psi 5205 9610
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I had my coach weighed at a truck stop with a full load during my trip two weeks ago. This is the results

Steer Axle : 8020 lb
Rear Axle: 15840 lb

Questions:
Do I take steer axle weight of 8020lbs and divide it by 2 so it's at 4010lbs per tire? And the same for the Rear Axle 15840/2= 7920

Those numbers seem too low for tire inflation based on my weight especially since my total gross weight was 23860lbs which I believe is the max for my Thor Challenger 37tb

Any feedback would be great, thanks.

Class A

15 Replies

MountainAir05
Explorer II
Aug 13, 2018
Should not the 15840 be divided by 4 for the number of tires on the rear.
Sam_Spade
Explorer
Aug 13, 2018
dotcommer wrote:
And the same for the Rear Axle 15840/2= 7920

IF....you have duals on the rear, 4 wheels total, then you would divide by 4 to get a per tire number.

AND....isn't there a plate or sticker somewhere with recommended pressures ?? You should be safe using those in most situations.
Ivylog
Explorer III
Aug 13, 2018
I add 5 psi to the table #s for various reasons so 80 front and 90 rear.
rk911
Explorer
Aug 13, 2018
i have the same tires and my weights are similarvto yours. i run 85 all around.
DrewE
Explorer II
Aug 13, 2018
You are figuring correctly. Each axle has two ends, so you divide the axle weight by two (and maybe add a little bit of a fudge factor since it's unlikely that the weight is perfectly balanced left to right). Something like 80 psi for the fronts and 85-90 psi for the rears would seem about right.

The tires can safely be used on vehicles a good bit heavier than your motorhome. That's not at all a bad situation to be in.