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-   -   Adjust tire pressure for cold weather?? (https://www.irv2.com/forums/f258/adjust-tire-pressure-for-cold-weather-558461.html)

ldfeat 10-24-2021 05:27 PM

So, if I check tires on a cold morning and find that they are low by 10lbs, I'll drive a few miles to find a place to air them up. Of course driving will heat the tires and increase the pressure, so I'll merely put ten lbs in the tires no matter what the heated tire pressure is raised to. So, if the tires were at 90psi before driving, and they are supposed to be 100, I'll put 10 more lbs in them even if it raised to 100 because of driving heat. Just a FYI...Larry 2014 Reyo P

PBK Images 10-24-2021 06:22 PM

My understanding from Michelin is that the standard temp they use is 68F. Assuming that my OAT in the morning is 45F, and my front tires (with the weight that I am carrying) is recommended to be a minimum of 117psi. But I could go up to the max limit of the tire and/or wheel, say 130PSI, my inflation goal at 45F will be the minimum (117 PSI). Why? Because I know that the OAT will increase during the day and the tire temp will increase as I drive. Just using common sense. If it is much colder, say, 35F, and I know that after a mile or two the tires will heat up to 45F and then continue heating, I might "cheat" a pound or two and inflate to 115psi to avoid higher psi at operating temps. Everyone has their own thoughts.

Max Headroom 10-24-2021 07:02 PM

Quote:

Originally Posted by MN_Traveler (Post 5961499)
Lol. Sorry. I HAVE driven through such large ambient temp fluctuations that adjustment (in both directions) , even within the same day, was needed. Does not happen often, but it can.

That's a serious case of overthinking, on steroids. OTR trucks go from places like Denver to Phoenix in one trip, in one day. Trust me, they are not doing this.
Are you adjusting your tires for fuel burn every couple of hours too?


A tire that is running and up to temp will be just fine, even if you go from Death Valley, to Vail. Checking the cold pressure where ever you are in the morning will be close enough, and what is recommended on the data sheet for the cold load pressures. There is no hot pressure table for any commercial tire that I've ever seen.
If the tire mfgrs thought this was necessary and prudent, they would recommend it, and they don't. Same goes for whats in the coach owners manual. As others have said, all this has already been thought of by the tire makers, when they published the cold inflation specs.
And if you are 'interpolating' what your hot TP 'should be', and adjusting based on that, then you're basically just guessing, and certainly not following the mfgrs recommended safe practice.


For a while, I've been scratching my head as to why so many RV's have blow outs, and I think I have my answer...

MN_Traveler 10-24-2021 07:22 PM

Quote:

Originally Posted by Max Headroom (Post 5961724)
That's a serious case of overthinking, on steroids. OTR trucks go from places like Denver to Phoenix in one trip, in one day. Trust me, they are not doing this.
Are you adjusting your tires for fuel burn every couple of hours too?


A tire that is running and up to temp will be just fine, even if you go from Death Valley, to Vail. Checking the cold pressure where ever you are in the morning will be close enough, and what is recommended on the data sheet for the cold load pressures. There is no hot pressure table for any commercial tire that I've ever seen.
If the tire mfgrs thought this was necessary and prudent, they would recommend it, and they don't. Same goes for whats in the coach owners manual. As others have said, all this has already been thought of by the tire makers, when they published the cold inflation specs.
And if you are 'interpolating' what your hot TP 'should be', and adjusting based on that, then you're basically just guessing, and certainly not following the mfgrs recommended safe practice.


For a while, I've been scratching my head as to why so many RV's have blow outs, and I think I have my answer...



Max - dont be nasty ... that was uncalled for.

When i drove from warmer to subzero temps, my tire pressures went from significantly above the min inflation (cold), down to the min inflation, WHILE I WAS DRIVING. I was concerned about them dropping lower if i stopped for any length of time.

I believe truckers usually just run the sidewall pressure. But then again, the trailer contents is usually not too worried about the quality of the ride...

I think im done with thread ... you folks do what you want to. (Ive heard some pretty dangerous practices here)

Crasher 10-24-2021 07:51 PM

Is there any topic that has as many opinions than the Tire Pressure saga? There is a Sticky with proven facts from an actual tire engineer/expert available to all, and yet, rather than read it, another tire pressure question is posted and more non-expert opinions are offered. :banghead:

Kid Gloves 10-24-2021 08:10 PM

Quote:

Originally Posted by PBK Images (Post 5961673)
My understanding from Michelin is that the standard temp they use is 68F. Assuming that my OAT in the morning is 45F, and my front tires (with the weight that I am carrying) is recommended to be a minimum of 117psi. But I could go up to the max limit of the tire and/or wheel, say 130PSI, my inflation goal at 45F will be the minimum (117 PSI). Why? Because I know that the OAT will increase during the day and the tire temp will increase as I drive. Just using common sense. If it is much colder, say, 35F, and I know that after a mile or two the tires will heat up to 45F and then continue heating, I might "cheat" a pound or two and inflate to 115psi to avoid higher psi at operating temps. Everyone has their own thoughts.

There is no standard temperature. Where did you find a load and inflation chart that recommends 117psi? You need to round up in 5psi increments to 120psi. Why would you ever inflate to less than the recommended minimum cold pressure?

Higher psi at operating temperatures is normal. Itís physics, itís inescapable. You are not using common sense.

NXR 10-24-2021 08:20 PM

Quote:

Originally Posted by jrgator
So, I leave Florida in a couple of weeks with the morning ambient of 75. In North Carolina two days later when the morning ambient is 40, should I raise the Florida pressure from the Michelin recommended 85 to 90 before I leave as a hedge against the low pressure in N.C.?

The minimum pressure I use is 90 PSI. "Minimum" as in not underinflated at all and coincidentally is also the inside DOT sticker. So 90 PSI can fully support the GAWR of each axle.

I usually set the tires to 98 or so to give me some temperature margin.

When I leave Florida at the end of March I bring all of the tires up to 100 PSI from the 95 PSI or so they usually are at that time.

When I arrive in Cleveland, OH and the temps are in the low 40's to high 30's, the next morning the tires are sitting at 90 PSI or a tad more.

It works for me.

We'll be leaving here in late December for Florida so I'll have the tires here at about 95 PSI. Whatever they are when we get to Florida will be where they stay unless somehow they are over the maximum sidewall cold pressure of 110 PSI. That has not happened yet.

I put air in the tires twice a year, when we leave Florida in early Spring and in the late Fall before we leave northern Ohio.

FWIW,

Ray

BigBillSD 10-25-2021 09:40 AM

Why wouldn't the tire pressure recommendations be to a corrected temperature like maybe 70 degrees? Using a TPMS allows you to see your tire pressures rise within a minute or so of starting to drive. My tires usually run at the same (130lbs) pressure when its 60 degrees outside and at 110 degrees outside, and they start at 115lbs cold. I have watched that many times driving from San Diego over toward Yuma on the way out of town. Changing the pressures every morning due to the outside temperature sounds more like an old wives tale.. (or more appropriately a senile engineer's tale) Or, we have always done it that way mentality. Within a few minutes your tires are hot. Maybe we are saying that its those first couple miles that kill the tire, as after that the pressure & tire temp rise pretty fast. -Bill

PS. This should "heat" up the discussion..

Kid Gloves 10-25-2021 11:10 AM

Quote:

Originally Posted by BigBillSD (Post 5962319)
Why wouldn't the tire pressure recommendations be to a corrected temperature like maybe 70 degrees? Using a TPMS allows you to see your tire pressures rise within a minute or so of starting to drive. My tires usually run at the same (130lbs) pressure when its 60 degrees outside and at 110 degrees outside, and they start at 115lbs cold. I have watched that many times driving from San Diego over toward Yuma on the way out of town. Changing the pressures every morning due to the outside temperature sounds more like an old wives tale.. (or more appropriately a senile engineer's tale) Or, we have always done it that way mentality. Within a few minutes your tires are hot. Maybe we are saying that its those first couple miles that kill the tire, as after that the pressure & tire temp rise pretty fast. -Bill

PS. This should "heat" up the discussion..

Well Bill, there is information provided by tire manufacturers from which knowledge can be gained.

inkahauts 10-25-2021 12:52 PM

If you really want to worry less about fluctuations in pressure you could find a place that could drain all the air from your tires and replace it with nitrogen air. It will have far less fluctuations between cold pressure and driving pressure. And then only add nitrogen air when it needs any more at some point.

BigBillSD 10-25-2021 01:22 PM

Quote:

Originally Posted by Kid Gloves (Post 5962455)
Well Bill, there is information provided by tire manufacturers from which knowledge can be gained.


I have, but so far only Michelin mentions it. And now that I look on their site for a few minutes, I have not found it. Michelin gave us a handout during an escapees seminar, and theirs said tire pressures should be corrected to 68 degrees on what I remember was an official glossy Michelin handout. Its too bad that this last year I was so bored the first couple months I started purging the house of unneeded crap. All that old paperwork went into the recycle bin. I don't use Michelin's anyway.

I only top up my tires when its around 70 degrees in the morning. They have about 50k miles now, and will be aging out in the next couple years. -Bill

Kid Gloves 10-25-2021 02:50 PM

Quote:

Originally Posted by BigBillSD (Post 5962648)
I have, but so far only Michelin mentions it. And now that I look on their site for a few minutes, I have not found it. Michelin gave us a handout during an escapees seminar, and theirs said tire pressures should be corrected to 68 degrees on what I remember was an official glossy Michelin handout. Its too bad that this last year I was so bored the first couple months I started purging the house of unneeded crap. All that old paperwork went into the recycle bin. I don't use Michelin's anyway.

I only top up my tires when its around 70 degrees in the morning. They have about 50k miles now, and will be aging out in the next couple years. -Bill

Perhaps Michelin punted on the idea of a temperature correction factor after realizing that a large percentage of owners canít figure out how to properly inflate their tires when give the simplest of instructions.

MN_Traveler 10-25-2021 03:15 PM

Quote:

Originally Posted by inkahauts (Post 5962601)
If you really want to worry less about fluctuations in pressure you could find a place that could drain all the air from your tires and replace it with nitrogen air. It will have far less fluctuations between cold pressure and driving pressure. And then only add nitrogen air when it needs any more at some point.

oh my .... not this again. Air is almost 80% nitrogen, most of the rest of the balance being oxygen. Both of these gases behave almost identically to each other to changes in pressure and temperature (ideal gas law). I am afraid that this commentary that continues to propagate that nitrogen filled tires will vary less in pressure than air filled tires is, with apologies, just plain not right ... and this is fact and data based, not just opinion. And yes, I can supply that data if someone says "where are the data"

Nitrogen filled tires do have a place - if it is dry nitrogen, when used over 5 years or so, might reduce the internal damage to the tire due to oxidation and hydrolysis or rusting of metalic components (damage by chemical reactions with water). I also understand (dont hold me to this though) that in racing and jet planes, nitrogen filled tires can be used to reduce the risk of fire due the presence of oxygen that would otherwise be in filled tires ... and also to reduce the damage that oxygen can do to tires. But nitrogen has no effect on the tires ability to hold pressure, or reduce pressure changes with temperature.....

(ok ... I broke my promise to stay away from this thread. Tireman and Crusher .... PLEASE, hold my arms behind me and hold me back..... :-)

Cass Sumrall 10-25-2021 03:18 PM

Quote:

Originally Posted by Fiesta48 (Post 5956829)
Way over kill posted here. Check all tires in the spring and fall. And just before each trip. 5 psi difference due to temps won't hurt any tire.
Low pressure will. Doing this for 60+ years.

Agreed!


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