Tire temps and pressures in summer

[Mr&MrsSmith]

Now that I have the EEZ TPMS, I need more info on how to monitor the tires. Coming back from our recent trip, the right rear tire got up to 108 degrees and about 97 psi. I called Discount Tire since they're the "experts" on tires, and asked how do I know if the tire is getting too hot and pressure is rising too much. The guy told me as long as the tire doesn't exceed the max psi. What? Max PSI on Goodyear Endurance on my 5er is 80 cold and that's what they recommend to put in them for running psi. So I'm supposed to only put 60 psi and let them heat up to 80 psi? I don't think so. So what temps and psi do the tires have to reach before I get concerned? Anybody know?

We just put the Endurance tires on our Eagle 5er last season and have the EEZ TPMS, I fill to 75psi. The rise is about 7-10 degrees depending on the tire location, weather condition, etc.

 

[Johnynorthland]

I had a warranty issue on my tow dolly tires so I called the manufacturer and had them replaced. I had asked the rep about over inflation since cold PSi is. 90 and told him many people on the internet say they start out at 80-85 cold. Instead of giving me mis-information he talked to the engineers who actually design the tires! Here is what they said;

Cold tire pressure must be set properly (mine at 90psi),otherwise the tire can and will blow out due to under inflation and overloaded weight. The tires are designed to inflate at a much higher inflation pressure as they heat up and expand. As far as heat they told me a tire would have to heat up to over 250 degrees F before it would have an issue or be dangerous. So I monitored my top pressure and set my Alarm about 10 degrees over that.

 

[Johnynorthland]

Also I noticed tires on the side facing the sun or near your exhaust will run hotter than the others.

 

[rkymntsno]

I had a warranty issue on my tow dolly tires so I called the manufacturer and had them replaced. I had asked the rep about over inflation since cold PSi is. 90 and told him many people on the internet say they start out at 80-85 cold. Instead of giving me mis-information he talked to the engineers who actually design the tires! Here is what they said;

Cold tire pressure must be set properly (mine at 90psi),otherwise the tire can and will blow out due to under inflation and overloaded weight. The tires are designed to inflate at a much higher inflation pressure as they heat up and expand. As far as heat they told me a tire would have to heat up to over 250 degrees F before it would have an issue or be dangerous. So I monitored my top pressure and set my Alarm about 10 degrees over that.

Good info, thanks. My EEZ TPMS says during setup to set the temp alarms to about 158 degrees, I think it was.

 

[norty1]

158 deg. is the standard that TST recommends on their alarm equipment for temp alarms.

I'm set mine yesterday as per the door sticker on the truck. fronts 60psi, rear 80psi. Fifth wheel tires at 100psi.

I expect then to heat up here in 95 degree ambient temps but that's the way I run them and I never had a high pressure alarm. High pressure alarm is set for 20 deg. over cold tire pressure.

 

[DNelson-JAY]

If you want to know what a professional tire engineer has to say about tires, including temperature and pressures, go to Roger Marble's website. Here is a link to his section on proper inflation:

RV Tire Safety: Cold Inflation

And below is a quote about Cold Inflation Pressure from one of his postings:

"The definition from US Tire & Rim Association is:

Cold Inflation Pressure is the inflation pressure taken with tires at the prevailing atmospheric temperatures and do not include any inflation build-up due to vehicle operation

In real life this means before the tire has been driven one mile. It also implies that the tire has not been exposed to external warming from being in Sunlight."

 

[Jim Smyth]

Quote:
Originally Posted by Jim Smyth
My TV and my trailer are both 80 psi max cold. I dont have monitoring on the trailer so I use my TV TPMS as a guide. Before the day gets going I like to keep the cold tire pressures around 74-75psi. This way when they heat up they are not too much higher than 80. To me 80 is 80 and I dont like pressing limits ever. Highest they usually get is around 83-84psi. I normally see about a 7-8psi rise in pressure.

Completely wrong! Your hot pressure is supposed to be higher. It's max pressure cold, not max cold and hot. Please read what the tire manufacturers have on their websites.


Earl

Am I really Earl? I am running Goodyear Endurance St225/75R15 tires. Here is a copy of the tire info from the manufacturer. I am well under the weights I need to be at to run safely at 74-75psi.

 

[GHen-JAY]

Earls comments are regarding hot pressure, your chart only shows cold pressure. The more pressure up to the max, the higher the load. Tire wear at low pressures is another separate subject. I’m sure there is a separate chart for expected hot pressure for each load/pressure level.

If your running 70 pounds cold the manufacturer is expecting them to get to 90, plus 20 pounds, I need to find the quote from the manufacturer where I found that. I run 80 pounds because I want the max load and have my high pressure alarm set to 98.

 

[Mopar_Earl]

Quote:
Originally Posted by Jim Smyth
My TV and my trailer are both 80 psi max cold. I dont have monitoring on the trailer so I use my TV TPMS as a guide. Before the day gets going I like to keep the cold tire pressures around 74-75psi. This way when they heat up they are not too much higher than 80. To me 80 is 80 and I dont like pressing limits ever. Highest they usually get is around 83-84psi. I normally see about a 7-8psi rise in pressure.








Am I really Earl? I am running Goodyear Endurance St225/75R15 tires. Here is a copy of the tire info from the manufacturer. I am well under the weights I need to be at to run safely at 74-75psi.

Yep, according to your original post you're under inflating so the hot pressure is close to your cold pressure. That is completely wrong. Cold pressure is cold pressure. At least that's what you said you're doing. I can only go by what you post. Also the 80 is 80 comment isn't correct either. 80 cold is 80 cold, not hot. The pressure will be and is supposed to be higher as the tire heats up. So 80 cold you will see well over that when the tire gets up to temp.

Then now you post you're running the lower pressure cause you're within the weights for the lower pressure. I'm not sure what your goal is at this point. But if you scaled and you know the exact weight on the tires and you use the chart, that is correct. But your original post is not correct at all. Any owners manual or tire manuals will show you the light on cold inflation.
I just don't want someone thinking cold pressure is hot pressure. That's dangerous to under inflate a tire to limit it's hot pressure.


Earl

 

[Scott_Trailer_Newbe]

Going through salt river canyon in Az last week, tires were at 77 PSI on the rear of the truck and all on the trailer. We went up to 86 PSI on the 4 hour trip. I wanted to let some air out and the 1/2 way point but decided to just go for it. All ended well.

 

[Mopar_Earl]

Going through salt river canyon in Az last week, tires were at 77 PSI on the rear of the truck and all on the trailer. We went up to 86 PSI on the 4 hour trip. I wanted to let some air out and the 1/2 way point but decided to just go for it. All ended well.

Never reduce hot tire pressure, that will cause under inflation! Please read your owners manuals. They clearly say to never lower hot tire pressure. Tire pressure is checked cold, not hot.


Earl

 

[Jim Smyth]

No where in my post did I say I was reducing hot tire pressure. That was something you decided to interject and said what I was doing was completely wrong. Well it isnt completely wrong. I said I start a little lower than MAX cold with with my 74-75psi and the manufacturers chart shows I am well below what my 5th wheels weight is even at max capacity. I loose about 100# per tire weight carrying capability at the start. After 5 minutes of towing I am at 80+ psi and just fine. I will continue to do it this way since I dont like to limit out on anything. I have never run anything at max cold in my life be it my personal family vehicles or any trailers I have pulled.

 

[Mopar_Earl]

No where in my post did I say I was reducing hot tire pressure. That was something you decided to interject and said what I was doing was completely wrong. Well it isnt completely wrong. I said I start a little lower than MAX cold with with my 74-75psi and the manufacturers chart shows I am well below what my 5th wheels weight is even at max capacity. I loose about 100# per tire weight carrying capability at the start. After 5 minutes of towing I am at 80+ psi and just fine. I will continue to do it this way since I dont like to limit out on anything. I have never run anything at max cold in my life be it my personal family vehicles or any trailers I have pulled.

Copied and pasted from your post.

"I like to keep the cold tire pressures around 74-75psi. This way when they heat up they are not too much higher than 80. To me 80 is 80 and I dont like pressing limits ever."

Never said you were reducing your hot pressure. I said you were lowering your cold pressure to limit your hot pressure from your own words that I copied and pasted. Like I said, I can only go on what you posted.

My last reply on your post, I'm rolling on.


Earl

 

[Springhook]

Copied and pasted from your post.

X2

"I like to keep the cold tire pressures around 74-75psi. This way when they heat up they are not too much higher than 80. To me 80 is 80 and I dont like pressing limits ever."

Never said you were reducing your hot pressure. I said you were lowering your cold pressure to limit your hot pressure from your own words that I copied and pasted. Like I said, I can only go on what you posted.

My last reply on your post, I'm rolling on.


Earl

I had a conversation with the Sailun tire rep regarding max cold temps. My Sailuns say 110 psi cold on the side with a max load of 3750 psi. My trailer scaled weight 11680. Rep said 110 psi was too much and to go to 95 psi. cold BASED ON LOAD.

 

[rkymntsno]

Well I've learned a lot since starting this thread. Jayco says to run the Goodyear Endurance at 80 psi cold. I will continue to do that. I will monitor all temps and pressures and not start to worry unless one tire increases temp and/or pressure, like the right rear did but only up to 108 degrees on a 95 degree day traveling 7 hours at 65-70 mph.

 

[Mopar_Earl]

I had a conversation with the Sailun tire rep regarding max cold temps. My Sailuns say 110 psi cold on the side with a max load of 3750 psi. My trailer scaled weight 11680. Rep said 110 psi was too much and to go to 95 psi. cold BASED ON LOAD.

That is a correct way of doing it. You scaled and know what weight is on your tires and inflating them to the tire chart and not guessing. Therefore you can run less if you choose to do so.
I have scaled several times but it's just easier for me to run max. Especially since I roll at 70 to 75 mph.
On my truck I run less than 80 in the rear during the winter no towing months. 80 is just too much for an unloaded truck. Much better ride. When towing season hits I run the door sticker pressures.


Earl

 

[norty1]

That's the same logic I use on my G614's. The side wall says cold 110 psi cold. The load I need to carry is more than adequate when I inflate to 100psi cold and also my rims have some max psi room.

I've been happy with the combo for 5 years.

 

[rdcox]

Tire Pressure

My recommended is 60psi on my trailer tires. I have sensors attached with a 10% warning tolerance. The tolerance is probably too low as my warning goes off constantly. The 10% is the sensor manufactured recommendation. I use TST sensors. Any thoughts?

 

[GHen-JAY]

I have been reading a lot of posts here and a lot of articles about rising tire pressure. It has been very educational for me, thank you everyone. I’m sure some of this information in the next paragraph is flawed, but here is some more info I have gathered.

Tire pressures supposably increase about 1 pound for every 10 degrees of outside air temperature increase. Tire pressure will also decrease 1 pound for every 10 degrees air temp decreases. The bust pressure for an average tire is around 200 pounds. Under-inflation under load causes an increase in sidewall temperatures and possible issues removing water from the contact area in wet conditions. Over-inflation causes a smaller contact patch reducing traction especially in wet conditions. Tire temperatures over 200 degrees increase the possibility of failures.

Now for my opinions.
Tire pressure decisions need to include load and air temperature calculations. I have no problem with running 60 pounds in my truck rear tire with no 5th wheel, while increasing to 80 while towing. A trailer would normally always have about the same load, but may need pressure adjustments based on traveling into extreme temperatures. If you are already in the extreme temperatures, temperature is already affecting the pressure of the cold max on the tire.

In my mind, the TPMS is there to warn us of many issues, the least of which is exceeding a possible tire pressure of 200 plus or minus bursting problem. Tires need to be inflated using charts of load requirements as well as expected air temperatures during the trip. Driving through the Dakotas in winter may require different pressures setups than Arizona in the summer and may require adjustments when leaving those extremes.

More importantly to me, tire pressure and temperature increases are also an indication of my brakes or bearings overheating. Allowing cooling or repairs to those devices could reduce the possibility of a catastrophic failure in the middle of nowhere.

I have no issue with anyone disputing the info above, the more I learn from others, the less likely I’ll be stranded somewhere inconvenient, or worse, in an accident.

 

[videoarizona]

I'm with you Ghen. The max cold tire pressure on the sidewall is the starting point for cold tire inflation. Then add the load element. If one isn't sure of load, air up to max cold on tire and you will be fine. Your tire wear will also be better in the long run. If you KNOW your load, then set accordingly.

This is really simple stuff.

Been in Arizona for all my adult life and have motorcycles, sailboats and travel trailers...along with trucks and SUV's for TV's....not one blow out in all these years. My bearings last almost forever as well. I run cold max pressure when under load. Drop pressure by 2 to 4 lbs when not towing. Everyone is happy.