Max pressure / pressure increase while driving

[acadiaforever]

2018 310 GK, Westlake G tires, TST TPMS. Recommended inflation pressure is 110#.

My question has to do with the expected increase in pressure while driving. I check inflation each morning to ensure starting at 108 - 110#. When I talked with the TST guys at Goshen, they recommended setting the low pressure alarm -10% and the high pressure alarm +20%, or 132#.

We're now driving in the southwest (New Mexico), and today one one of the sun-side tires hit 132 and alarmed. I checked the other tires, and the other sun-side tire was 129, and the shade side were both 127. (I think--I was mostly concerned with the sun side. If not 127, 126.)

You all have a lot more experience on the road than I do. What are you all experiencing with tire pressure while underway; how much increase is to be expected? Is 132 a reasonable alarm pressure, or is that an expected pressure and I should bump the alarm another ~5#?

Thanks for any advice.
-Al

[bertschb]

I'm no expert but I'll share what I do...

We live at 4,200' in Central Oregon and it's cold here in the morning when we head south for the winter so I set the tire pressure in the 5th wheel to about 103psi. I'd probably start at 110psi if it was 60 degrees but it's more like 20 when we leave. By the time we drop down into central California it's usually 50 degrees warmer and our tire pressures will have increased to 115 to 120psi. I don't like my pressures to exceed much more than the low 120's and if they do, I'll drop some air while en route.

My example is kind of extreme because of the temperature difference between our departure and destination. I don't worry about the difference in tire pressure between the sunny and shaded side of the RV.

EDIT: This is what we did with G rated tires on our Reflection. Since our new Solitude is heavier, I'll probably start at 105psi at 20 degrees ambient temps.

[DaveMatthewsBand]

Imagine your trailer is facing North in the morning when you leave, at say 9am, and your passenger side tires are all reading 115 psi because they’re in the sun, but your driver side tires are reading 105 psi, should you go ahead and add 10 psi to the driver side tires so they’re all the same?

And if you did, then turned and drove due South at 2pm, wouldn’t the driver side (shaded) tires go down in pressure while passenger side (sunny side) tires increase in pressure because they’re now in the sun?

- Carl Jung


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[RobertS377]

This is a concern i always have. We regularly travel from MD to FL and temps rise considerably as we head south

I often wonder about adjusting to compensate for ambient temps until I read this on the Goodyear site:

“For every one psi a tire is underinflated, you will lose approximately 20-30 pounds of load-carrying capacity per tire (varies based on tire size and single- or dual-tire application)”.

It further stated that lower pressure allows the sidewall to flex more, thereby causing heat and pressure increase.

I concluded I should not lower the cold psi

I just put new GY Endurance on yesterday and we won’t be on the road until next Monday. The installer said the temps on these will not likely increase as much as they did on the Westlakes we had because the sidewall will not flex as much. That’s consistent with what i read on the GY site as well

My Westlakes would increase about 12-14% going from 80 cold psi to 92-94. That always bothered me as it approached 96 because that would trigger my TPMS which is set to 20% high alarm (Per my tpms manual) From what I read 8-10% is the norm.

I’m interested what I’ll see with these next week

Bob

[warsw1]

I always run my tire pressure at 110 cold. As I travel I will typical see a 15% increase in pressure. I have my high pressure alarm set at 135 psi and have never set it off. I have seen it at 132 however. I never adjust for the difference you might see because of one side being on the sunny side. Usually the heat buildup from going down the road will outrun any heat added from the tire being on the sunny side and they will all end up running near the same pressure/temp.

[D2Reid]

Reaching 15% higher than cold pressure is normal for me. My high side alarm is around 139, and I have set it off. Hot day, sunny side. The only time I had a flat with a G614 the TPMS was indicating 140 and we had been running hot for several hours. My old trailer

I set my tires to 110 cold, they usually run 125-130. I have seen 130-135 with my new Momentum but that was running on hot days. If it should go over 137 I will become concerned.

[Airrace]

interesting. I was wondering what the trailer tires were doing. I do not have monitors on the trailer tires. The new truck has sensors and I have seen the fronts go from 75 psi to 92 psi and the rears go from 65 to 80 at times. I am running around 105 for now on the trailer.

[DaveMatthewsBand]

I noticed on my GY tires it says "For Maximum Load" inflate to 80 psi.
Max load is 2830 per tire but I'm 580 lbs shy of that, per tire.
So the load is actually only 80% of max.
So maybe I should run the tires at 64 psi which is 80% of 80 psi?



In order to keep people (like me) from guessing they should just print on each tire "inflate to 80 psi or you will die".

[RVRunners]

I noticed on my GY tires it says "For Maximum Load" inflate to 80 psi.
Max load is 2830 per tire but I'm 580 lbs shy of that, per tire.
So the load is actually only 80% of max.
So maybe I should run the tires at 64 psi which is 80% of 80 psi?



In order to keep people (like me) from guessing they should just print on each tire "inflate to 80 psi or you will die".

When we went through the CAT scale recently we had around 11,000lbs on our two 7,000lb axles but I maintain my cold pressure at the maximum rated on the sidewall. It is likely that the sticker on your RV calls for the tires to be at your max 80 (my sticker calls for 80psi on the original 235 80 16 tires - I have since upgraded to F rated 235 85 16 tires which can handle 95psi so 95 is the cold pressure I maintain now). Low pressure is the enemy of any tire and increases the odds of failure. We run the EZTire TPMS and it also recommends alarms at -10% and +20% so I have it set up accordingly. Travel safely!

[Country Campers]

I noticed on my GY tires it says "For Maximum Load" inflate to 80 psi.
Max load is 2830 per tire but I'm 580 lbs shy of that, per tire.
So the load is actually only 80% of max.
So maybe I should run the tires at 64 psi which is 80% of 80 psi?



In order to keep people (like me) from guessing they should just print on each tire "inflate to 80 psi or you will die".

Ed
I got my trailer weighed at the Indiana Rally this year and my tire weights where such that they said I could go from 80 psi down to 40 psi for the load I was carrying.
There is NO way I would do that. I am with you if the tire says 80 psi that is what I run. I do not have tire monitor.

Brian