Tire inflation

I'll add my 2 pennies here. I have just replaced my tires and during my research from various tire companies, I have been told that you should have at least 10 psi below maximum on the steering axel. On the rear duals if the PSI is suggested to be 75 psi it should be a max of 70. The reasons given are for stability and anti wandering. Plus unless you have the same tires the MH came with new there is always a variation.
I spent hours researching tire and size in order to stop wandering and increase stability. Both have achieved my requirements and my receipt shows tire pressures. It should also be remembered no two MH are loaded or driven the same way, and any sop suggestion is a suggestion and not a 100% recommendation.. Talk to a tire guy then go else where and talk again.. when you get the same response three time act on it.

This states what I have always written , and that is that the AT-pressure is not the maximum pressure of the tire.
Its as 3 times written by topflite51 the minimum needed pressure to carry the maximum load given on tire sidewall.

If I would calculate pressure for GAWR, and motorhome rear axle mostly begins in normal use at GAWR , I would add even 18% to that load for absolute savety, so if real load is higher or on one tire half load is higher because of weighdifferences R/L. stil the deflection of tire is that low that no tire damage begins at higher speed.

If then real load is lower then GAWR this pressure can give some discomfort and lesser gripp , but this is less worse then tire damage, and the missery that can go with it.

When real loads on seperate tires are known by weighing , less reserve can be used. and so here again , try to get the motorhome weighed in loading you use when driving , at best per wheel(pair) , second best per axle.

Have posted this before, but here it is again:

19.5 and larger the following is correct: Michelin RV TireGuide: Quote: "If you look at the tire's sidewall, you'll see the maximum load capacity allowed for the size tire and load rating, and the minimum cold air inflation needed to carry the maximum load." From page 6 of the GoodYear RV Tire and Care Guide: Quote: "How much air is enough? The proper air inflation for your tires depends on how much your fully loaded RV or trailer weighs. Look at the sidewall of your RV tire and you’ll see the maximum load capacity for the tire size and load rating, as well as the minimum cold air inflation, needed to carry that maximum load." From the August 2010 Motorhome Magazine "Tread Carefully" tire article: Quote: The maximum load capacity allowed for the size tire and load rating and the minimum cold air inflation needed to carry that maximum load are located on the tire’s sidewall. So if one has not weighed their rig, then the min tire pressure on the sidewall should be used until they have weighed their rig.

wolfe10 wrote:
The wall sticker, also known as the GVWR sticker has PSI's based on:

PROPER PSI IF, REPEAT IF EACH AXLE IS LOADED TO ITS GAWR (Gross Axle Weight Rating).

Hopefully, your actual weights will be under GAWR's, so the PSI required to carry your actual load will and should be less.

Makes perfect sense to me.

And to me now that you put it together. Didn't register that we were talking max. Thank you.

The wall sticker, also known as the GVWR sticker has PSI's based on:

PROPER PSI IF, REPEAT IF EACH AXLE IS LOADED TO ITS GAWR (Gross Axle Weight Rating).

Hopefully, your actual weights will be under GAWR's, so the PSI required to carry your actual load will and should be less.

Makes perfect sense to me.

wa8yxm wrote:
Well, with the duals it sounds like you are carrying about 2x the weight on the rear.. So

85 front times contact area is the load they can carry (At that pressure)

Same in the rear, only you have 2x the contact area cause you have 2x the tires.

It is not that simple but that is close enough I think to bring understanding.

(The rest has to do with heat dissipation and such, Duals not as good at it)

On some motor homes the rear may run "Softer" (lower PSI) on others higher On mine the same.

Thanks again for the forthright information and logic. On my previous winnebago 30 T I reduced the psi from 85 to chart recommended 80 and vastly improved the ride. Amazing what 5% less air does to expansion joints.

Well, with the duals it sounds like you are carrying about 2x the weight on the rear.. So

85 front times contact area is the load they can carry (At that pressure)

Same in the rear, only you have 2x the contact area cause you have 2x the tires.

It is not that simple but that is close enough I think to bring understanding.

(The rest has to do with heat dissipation and such, Duals not as good at it)

On some motor homes the rear may run "Softer" (lower PSI) on others higher On mine the same.

wa8yxm wrote:
The folks who stuck the sticker have to make a few assumptions... Like how much weight you are going to carry.

So, if you happen to load your rig in EXACTLY the manner they assumed, their pressure rating is proper..... What are the odds of you doing that (Approach zero)

You are, however, only 5PSI over the upper recommended... Many folks suggest running 4 PSI over tire maker's recommendations... I will not argue with them at all... So run 85-90 would be my suggestion.

Thanks. I reduced from about 91 to about 86 on front and went for a short ride and it made a nice improvement. I have Kelderman air ride on front so the ride is already pretty good. I am striving for perfect. I will trade a couple of years of wear for good ride. Couldn't do Kelderman on rear because of hot water heater location. I am putting Koni FSD's on next week. I am confused about the rear duals. According to weight divided by 2 I can run 85 easily on duals but always thought rears took a bit more psi than front. No info on that just something that seemed to stick in my brain.

We owned Class 8 trucks and always ran the Michelins high. They will wear longer and ride like you're on a washboard.

The folks who stuck the sticker have to make a few assumptions... Like how much weight you are going to carry.

So, if you happen to load your rig in EXACTLY the manner they assumed, their pressure rating is proper..... What are the odds of you doing that (Approach zero)

You are, however, only 5PSI over the upper recommended... Many folks suggest running 4 PSI over tire maker's recommendations... I will not argue with them at all... So run 85-90 would be my suggestion.