Tire Pressure ???

Though best is, as already written, is going from weighed seperate wheel(pair) weights , second best axle weights, as long as you did not do that, you can go from the GAWR's and add 10% for reserve.
You can find those GAWR's for front rear and tag often on the same plate as the original pressure advices.

Most motorhomes have a pretty constant weight and weightdivision, and often the axleweights around the GAWR's ( gross axle weight ratings, so what is maximum allowed to weigh).

A tag axle is to my knowledge an axle that can be put more or less pressure on the suspension , and even can be lifted off the ground .
You can chanche the division of total weight on the axles with it.
If you highen up the pressure on the ground of tag, less weight on drive axle and more on Tag and front axle.
This is when tag axle is placed behind the rear/drive-axle)
And the other way around , less tag-pressure ( so not the tirepressure of the tag tires) more on drive and less on tag and front.

You can use this if front or rear proves after weighing to go over gawr. and the other axles have a reserve.

If you can give me the configuration of your vehicle and the tire-data read from the sidewall, I am able to give you an advice pressure, calculated with spreadsheet I made and wich uses reserves and and extra save formula .

Need from vehicle next:
GAWR Front REar TAg, better weighed axle loads in the loading you use).
Howmany tires on the axles ( probably front 2 DRive 4 and tag 2).
And where the Tag is placed , behind drive axle or between front and drive axle.
ideal would be if you give your maximum used speed and wont go over for even a minute.

From tires I need at least the maximum load or loadindex, and the Pressure behind AT ( yours probably AT 110 psi = G-load/LRG or European notation 14 ply/Plyrated.
Or read from sidewall something like this "maximum load xxxx lbs AT yyy psi( cold).
Also would be nice if you can find the speedcode of tire,, but on american tires not always given, letter mostly L(max 120km/75m/h) M( max 130km/81m/h or N( 140km/87m/h) for these large , in fact truck tires.

If you can produce that data, I can give you an preliminary advice , as long as you did not weigh.

Greatings from a "Pigheaded Dutch Selfdeclared Tirepressure-Specialist"
Peter

Thanks to all for your input.
I had the Toyo M144 (not M154) 295x80 r22.5 installed today.
Inflated the duals to 95psi and they ran pretty good on the way
home (25 miles). If I experience and noticeable difference in future mileage I will post. Thanks

whatever the tire manufacture says for the weight of your rig!!!!

Yeah I agree with the others. Tire guy messed up. Your coach is engineered for the right psi.

Instead of replacing all six of my rear tires with 295s I went with 11R22.5. Same diameter and almost half the price. Had to increase the drive axle pressure by 10 psi from 85 to 95. Left the tag at 75 which is the minimum recommendation to keep the tire on the rim as it was already 10 more than actually needed. I rarely raise my tag and never had a problem with wear or coming off the rim in 80K miles.

wildtoad wrote:
Keep it simple.

OH NO....we can't have that.
If we did 2/3 of the posts we have on here would disappear. :B

If they are the same size, same load rating as what you have now, use the same pressure you use now or the placard. Keep it simple.

All shouldn't be the same and as said weigh and set according to toyos recommendations. There is an exception in the tag that several knowledgeable folks ( for what that's worth ) told me. My tag weight called for 80 lbs and I run 90. It was explained that the tag has s lot of scrub force on the sides. I had a les Schwab tire store refuse to put less in. I asked around and have kept them higher with no ride difference. As a truck driver We ran high pressures all around because of varying weights. I still run higher pressures on both rear ( 90 tag 100 drive ) as my handling isn't any different and I prefer the extra margin. Chart called for 80 tag 85 drive
What's your handling like with the higher pressures ?

^^^^^^^^^^^^^This is the correct answer. Does your tire "guy" know the actual weight of your rig? Four corners is optimal but second best is axle weights....Dennis


Toyo Inflation Tables

Weigh your rig and inflate as recomended by the tire mfg according to rig weight.