Tire Pressure question towing 80 F to 25 F?

[mountain bob]

i will be towing about 1300 miles in an F250. Tire psi in door says 60 psi for the front and 65 psi for the back. The tires say 80 psi measured cold. Temp change of 5 degrees F causes a 1 pound psi change.
The trip will go from 80 F temp to about 25 F temp. Is there a way to set the tires to allow a 10# change over this range without having to stop and add pressure or driving with overinflated or underinflated tires? Is the safe tire range a low of 60psi to a max of 80psi?
Any thoughts are appreciated. I asked this of 3 tire centers and got 3 different answers.

[TB673]

mountain bob, Welcome to the forum.
Here is a link to an article regarding 1st person experience with temps ranging from 33 deg. F to 95 deg F.
This article is taken from Tireman 9's blog. Roger is a retired tire engineer.
I hope that this may help.

https://www.rvtiresafety.net/2014/11...t-science.html

Tim

[JIMNLIN]

Your gonna' get about he same type of answers on this or any RV website.
I'v towed for a living in 110 temps down to teens temps in a 10 hour period and never aired my 15"/16"/17.5" tires up or down or up.
I set them cold max sidewall temps. Tires will gain psi back when rolling down the road in cold temp areas.
With 28 tires on the ground with various size trailers I never over tired those trailers to a point that max sidewall pressures was too much psi.
If your tires are properly sized per axle ratings ......Set them at max sidewall and enjoy the trip. I

[NXR]

The formula is a 2% pressure change up or down for each 10F of temperature change.

65 PSI * .02 = 1.3 PSI change per 10 F

80 - 25 = a 55F change.

5.5 * 1.3 = a 7 PSI change from 80F to 25F. Your tires can go to 80 PSI cold. The easy thing to do is increase the tire pressures to 70 and 75.

I don't know if you're asking about the truck or RV so be certain to me make the appropriate change in each one.

Ray

[deserteagle5]

That 80 psi on your tire sidewall is the MAXIMUM pressure the tires should have when cold. That DOES NOT mean that's what the tires need to run all the time. Tire pressure you should run depends on the weight of your rig. So if you have a pallet weighing 3000 lbs in the back of your F250 and you'll be doing a road trip then yes, inflate to 80 psi. If you will be running empty down dirt roads you shouldn't run over 50 psi.

I have several rigs wearing Load Range E tires. The dually with a slide-in camper in the back runs at 75 psi. The F150 runs at 36 psi. The Jeep Wrangler is at no more than 20 psi.

And no, there is no way to keep the pressure in your tires from increasing when the tires heat up. Set them at a pressure to handle the weight at the cold temperatures (and with the tires cold) and call it good. Even if the tires go up over 80 psi after they heat up, they are designed to handle that. That's MUCH better than running too low a pressure for the weight you are carrying.

[traveldawg]

I have towed from FL to the West coast, to Canada and back through 100 degree temps and down to probably 32 degrees or a bit less (and snowing) and don't adjust the tire pressure. I've done it many times and over many years and in different types of RVs. I set my truck tires per the label on the door jam. I set my RV tires based on weight (measured) and tire inflation charts.

I do monitor the pressures with vehicle's built in TPMS and RV TMPS system I installed.

Many mornings in the cold, and especially at high altitudes, the TMPS will report the tire pressure is low - like 5+ pounds. But after a few miles the pressure comes up and all is well. In high temps and moving the temps and pressure go up (well over 5 pounds, especially on the RV).

I attended a driving school once for Class A motorhomes on a Freightliner chassis - taught by/at Freightliner. Tire pressure advice was to set them for the altitude you are at (when at/around 70 degrees as I recall) per inflation and weight tables and generally leave it that way. Change it only if you will be at a different altitude for a long time (either higher or lower than where you usually are - and, again, at a temp in the 70s).

Hope this helps.

[mountain bob]

Thanks to you and everyone on replying to my concern. All the explanations have helped and I am not anxious now. I hope you all have wonderful days and joy on your trips. Blessings.

[Jay D.]

Originally Posted by JIMNLIN

Your gonna' get about he same type of answers on this or any RV website.
I'v towed for a living in 110 temps down to teens temps in a 10 hour period and never aired my 15"/16"/17.5" tires up or down or up.
I set them cold max sidewall temps. Tires will gain psi back when rolling down the road in cold temp areas.
With 28 tires on the ground with various size trailers I never over tired those trailers to a point that max sidewall pressures was too much psi.
If your tires are properly sized per axle ratings ......Set them at max sidewall and enjoy the trip. I

THIS! When i tow i air up to the cold max on the tire sidewall they are engineered to operate there for all temperatures.
Jay D.

[terrylane]

Originally Posted by TB673

mountain bob, Welcome to the forum.
Here is a link to an article regarding 1st person experience with temps ranging from 33 deg. F to 95 deg F.
This article is taken from Tireman 9's blog. Roger is a retired tire engineer.
I hope that this may help.

https://www.rvtiresafety.net/2014/11...t-science.html

Tim

Just to be sure I understand what Roger says in his article...

"Always running inflation about 15 psi above what is needed for actual max load based on 4 position scale weights that are confirmed to have not changed significantly each year with a trip across CAT scales."

Roger is saying, if your max load cold pressure is 90# from the tire manufacturer, and your rig is loaded to max weight, then your tires should be inflated to 105#?

[NXR]

Originally Posted by terrylane

Just to be sure I understand what Roger says in his article...

"Always running inflation about 15 psi above what is needed for actual max load based on 4 position scale weights that are confirmed to have not changed significantly each year with a trip across CAT scales."

Roger is saying, if your max load cold pressure is 90# from the tire manufacturer, and your rig is loaded to max weight, then your tires should be inflated to 105#?

"Max load cold pressure" is the sidewall pressure and that should not be exceeded when cold. Is that what you meant to write?

Many people do not understand that the tire load inflation charts are the MINIMUM pressure for that weight, not some kind of "recommended" pressure.

Many people do not understand that the tire load inflation charts assume each tire on an axle is supporting exactly the same weight. That's a reasonable assumption in a car or truck but not an RV, hence his"four corner" note.

The purpose in carrying extra pressure is to assure that in the range of expected temps and in the range of expected weight that no tire is ever below the tire load inflation chart number, when cold.


In that link Roger kind of mixed metaphors, so to speak. He was asked the question by a travel trailer owner and responded with his Class C experience and recommendation.

Generally any multi-axle trailer should be using the sidewall pressure as the cold pressure IF the original tire size and load range is still installed.

Ray

[Gr8bawana]

There is no need to adjust tire PSI when driving from hot to cold temps.
Do you see literature from tire manufacturers telling to make such adjustments? No you don't.

[MooseCountry]

Elevation gain also increases tire pressure by approximately 0.5 PSI per 1,000 feet. So if it's 80F in Florida with a mean elevation of 100 feet and 80F in Colorado with a mean elevation of 6,800 feet expect the tire pressure to increase slightly over 3 PSI during the trip. Assuming that the tires were filled up while cold in Florida and then driven to Colorado where they're rechecked while cold.

[wolfe10]

Originally Posted by MooseCountry

Elevation gain also increases tire pressure by approximately 0.5 PSI per 1,000 feet. So if it's 80F in Florida with a mean elevation of 100 feet and 80F in Colorado with a mean elevation of 6,800 feet expect the tire pressure to increase slightly over 3 PSI during the trip. Assuming that the tires were filled up while cold in Florida and then driven to Colorado where they're rechecked while cold.

But very likely the lower ambient temperature in Colorado vs Florida will mean you need to ADD air, as temperature has a much greater effect on tire PSI than does elevation.


Personal experience driving from Florida (elevation 18') to Angel Fire, NM (8,400') is I always have to add air in Angel Fire due to cooler (that is why we head there) temperatures.

[Old-Biscuit]

My truck has 80 psi MAX on sidewall
Front tires are at 60 psi
Rear tires are at 50 psi ....... when towing I air them up to 80 psi on morning of towing day

When not a towing day....rear tires go back to 50 psi/front tires remain at 60 psi all the time

Front tires at 60 due to weight of diesel engine
Rear tires at 50 psi due to nothing in bed of truck until tow day then weight increases due to Pin Wet of 5vr hence the 80 psi (COLD)