Curious about tire pressure on hot pavement

[buvens]

I have a Chevy 1500 with tires that say 44# psi at so much load and a trailer with
6 ply tires that recommend 50# psi

Was just curious what pressures I might see driving on hot highways in 90 degree weather?

Took the truck to fill it up with gas a couple of days ago and without the trailer the tires were running 49-50# psi.

Checked the truck tires the next morning and they were all at 44# psi.

Figured with trailer on the highway it would go some higher.

Was wondering what others experiences are?

Maybe even temperature also. Don't remember what tire temps were right now.

Thanks...

[RoscoeV]

When pulling your trailer or with a load, you should always fill your tires to the max pressure stamped on the tires when they are cold. The tire pressure will always go up as they get warmer and the manufacturers built that compensation it to the tires.

[travelin texans]

Check/adjust pressures when "cold", as in the morning before traveling, tires are at ambient temperatures. As stated the manufacturers have allowed for the increased pressures due to temperature.

[buvens]

When pulling your trailer or with a load, you should always fill your tires to the max pressure stamped on the tires when they are cold. The tire pressure will always go up as they get warmer and the manufacturers built that compensation it to the tires.

I knew the pressure would increase. Just curious how much others had seen.

Figure, I'll find out on mine this afternoon going west into the sun.

Thanks for the replies.

[Ken / Claudia]

On my f350, I have checked it. 80psi cold morning before trip start. Outside air temps not sure around 60f. Afternoon of all day driving heavy load in truck bed, outside air temps 110-115f in Redding CA. Rear tires were 94 and 96 psi. Weeks later I ask the tire shop guy, he says they are built to take that, those tires rated at 3740lbs each had about 3600lbs on them if I remember right.

[CWtheMan]

Because of the building materials and compounding, all tires are not equal when it comes to thermal expansions. For an explanation for your particular tire design, and usage, you can read the tire data book from the manufacturer of your tires. It will provide information about the normal temp range for your tires and the most common conditions that produce uncommon temps.

Thermal equilibrium plays a large roll in tire temps. Reading about it will help, if you're into those scientific conditions.

[Racebug]

my dually unloaded will go from 80psi cold to 91-92 hot. that's on a 70 degree day.

[rjrelander]

Yup, as others have said, rated pressure is "cold" which I believe is at least three hours after driving. If you don't have an air compressor (or use nitrogen), measure the pressure cold, subtract that from the value stamped on the tire, and then have the shop add the difference to the tires when you get there. Speaking of nitrogen, a lot of tire shops will top you off for free even if you didn't buy the tires there.

[jadatis]

Pressure advice is given for 65/68 degrF.
So cold measured pressure should be calculated back to that temperature. Cold is when inside tire temp = outside tire temp, that simple.
The tire inside warms up by driving .
So when 90 degr F outside , the tire inside warms up by driving to a higher temp.
Did I already mention that with temp rising in tire, the pressure rises too.
There is a range in outside temp at wich warming up by driving and cooling down is in balance so not any part of tire reaches a temp at wich the rubber hardens ireversible. So if you determined the right pressure for you situation, calculate it back to 65 degr F and you are safe.

[buvens]

Thanks for all the info.
here is what I saw.
On the 44# psi truck tires in stop and go on the interstate I saw up to 57#psi and up to 129 degrees. Mainly higher on front tires.
Once rolling around 55mph they cooled down to 51# psi and about 99 degrees.
Trailer tires got up to 57# psi and 105 in traffic and 97 once we were traveling.
Was interesting just seeing what they did on a 90 degree day.

[xrated]

I have a Chevy 1500 with tires that say 44# psi at so much load and a trailer with
6 ply tires that recommend 50# psi

Was just curious what pressures I might see driving on hot highways in 90 degree weather?

Took the truck to fill it up with gas a couple of days ago and without the trailer the tires were running 49-50# psi.

Checked the truck tires the next morning and they were all at 44# psi.

Figured with trailer on the highway it would go some higher.

Was wondering what others experiences are?

Maybe even temperature also. Don't remember what tire temps were right now.

Thanks...

Always set your tire pressure when the tire is "cold". There is no reference to a certain temperature for the meaning of cold. That reference is made to mean; When the tire is at ambient air temperature of the surrounding air. If it's 90 degrees outside and the tire has not been in use (cold) then set it to the correct pressure that is required....in your case, 44 for the truck and 50 for the trailer. The next day, you might have travelled to a location where the ambient temperature is 70 degrees when you wake up and before you start travelling. Adjust the air pressure to 44 psi for the truck and 50 for the trailer.

[jadatis]

Thanks for all the info.
here is what I saw.
On the 44# psi truck tires in stop and go on the interstate I saw up to 57#psi and up to 129 degrees. Mainly higher on front tires.
Once rolling around 55mph they cooled down to 51# psi and about 99 degrees.
Trailer tires got up to 57# psi and 105 in traffic and 97 once we were traveling.
Was interesting just seeing what they did on a 90 degree day.

Now on mobile phone so dont have speadsheets for temp/ pressure at hand.
But the pressure rising is not in line with the temperatures.
So I think you have sensors screwed on the outside on valves. This gives temp somewhere between in an outside tire temp.
At the stop you probably measured higher temp and pressure because yust after braking , wich heat is transported trough the rimms to the tire inside.
When I am on my handicapped laptop, I will give a tabel of pressure for temp.

[captcolour]

Sailuns on the 5er set at 110psi cold will run 125 - 129psi and generally around 100F when going down the highway.

[Johnnyfry]

All tire manufacturers publish a load VS pressure chart. The pressure (cold) you put in depends on load. The best way to determine this is to get weighed. You need the weight on each tire so if you weigh the front axle you divide by 2 to get the individual tire load. Same with the rear. If you have a Dully assume that each tire is 1/4 the axle load. Same for the trailer. Knowing the load on the tires you can go to the chart and read the cold pressure you need. If you are close to the max lead on tires this will probably be the max pressure stamped. Also be aware that the max rating for a tire will be lower for each tire on a Dually axle.

Don't worry that the pressure goes up after driving even a short distance, this is normal.

I hope this helps.
John

[johnlewis]

Truck's recommended tire pressures for max load should be set, based on 70 degrees F, for most accurate setting. We have a 5th wheel and dually, with TPMS on all tires. Tire pressures on the truck will rise as much as 12 psi when towing in 90 degree weather. 5th wheel tire pressures will rise as much at 18 psi, when it's hot. Pressure and temperature rises are expected by the tire manufacturers. If you are still concerned, go to the website for your tires, and ask the experts.

[buvens]

Thanks for everyone's replies.

I had just put on the TPMS on my TV and trailer and was wondering what to expect.

Now that I have used it awhile I know better what to expect.

Probably be higher with the summer coming.