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Max Pressure Cold vs Hot Pressures - How Much Is Too Much

Rollochrome
Explorer
Explorer
My Carlisle CSL 16's have a cold max pressure of 110.

I installed a TPMS the same day I bought them.

I read up on these tires and there was nothing about a hot max pressure from Carlisle. I contacted Carlisle and they said there was no "hot max" specified.

So on the maiden voyage with them, I watched the temps rise and rise above 110 to just under 120.

The tires on the sunny side were uniformly higher than the ones in the shade side understandably too.

I read elsewhere that a different manufacturer emphatically states on their website regarding trailer tires to NEVER bleed down HOT tires.

So it begs the question, how much hot pressure is too much? The TPMS system instructs to set alert levels that are pretty high.

What do you think is an acceptable pressure level hot relative to the cold max?
1999 Saved By Grace Alone Thru Faith Alone! Thank You Jesus!
2019 F-350 LWB 6.7 4wd XLT-FX4-3.31 on Michelin Defender LTX M/S
2022 3850BH Cruiser South Fork on Carlisle CSL 16
50 REPLIES 50

laknox
Nomad
Nomad
FWIW, the past couple of years, Discount has been inflating car/truck tires to a few lbs over sidewall in their free air check bays. It's because the tires are no longer "cold", due to just driving to the shop. My van's tires are rated 35 psi cold, so they regularly go to 39, especially in the summer. I've asked them a couple times when preparing for a summer trip and a loaded van, to go to 40. If I'm 1-2 over the next morning, I can live with that. With my daughter, s-i-l, and grandkids in the car, I ain't taking chances!

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

laknox
Nomad
Nomad
MFL wrote:
I think some of the tire inflation, disagreement, is due to talking about many different types of tire use. What works for cars, trucks, DRW trucks, motorhomes, and trailers, is not comparing apples to apples.

Most put the proper tires on their tow vehicle, and adjust as needed for load. I see some people buying way more tire than their trailer needs, then reducing pressure, way below max, when they should have just purchased the proper tire needed for the load, and aired for the load.

Jerry


I agree. My old Komfort, with 11,360 GVW, was placarded for D tires. At about 2550 lbs per tire, that put the tires UNDER the GVW; the rest is carried by the truck. Fine for most, but too close to the limit for me and, after I lost a tire in the 2nd year and another failure in the 4th year on the 2nd set of D's, I went to E's and ran 70-75 psi almost exclusively for the next 9 years and 2 sets. There were a couple occasions that I was running heavier than normal (extra ice, food and water) and I'd inflate to the full 80 psi. Using my temp "gun", the E's at 75 ran at least 5 degrees cooler than the D's ever did, and they were always inflated to 65 psi.

My current KZ, 860 lbs gross lighter at 10.5k, had D's and I replaced the original tires with a set of Endurance D's. So far, they're working well. I'd've gone with Carlisles to save some money, but Discount didn't have any and had none in their entire national inventory at that time. I was time-critical in that we had a camping trip planned and I only found the bad OEM tires (2) about 3 days before leaving.

Lyle
2022 GMC Sierra 3500 HD Denali Crew Cab 4x4 Duramax
B&W OEM Companion & Gooseneck Kit
2017 KZ Durango 1500 D277RLT
1936 John Deere Model A
International Flying Farmers 64 Year Member

Cummins12V98
Explorer III
Explorer III
Walaby wrote:
I agree... it is load limit, and if you exceed the load by a pound you should go to the next higher rating. BUT, my interpretation of Cummins 12v98's post is even if I were at or below the appropriate rating, he recommends adding 5 PSI. Just strikes me odd that he (and others) are so adamant about following the chart, but then decide on their own to only take it as a recommendation and create their own chart (in their mind).

Just an observation, nothing more.

Mike


As I just mentioned I follow what I was taught by GY Tech Support!!! I can tell you with many thousands of miles I have always had perfectly even tread wear.
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

Cummins12V98
Explorer III
Explorer III
Walaby wrote:
Cummins12V98 wrote:
Over/under MAX has nothing to do with "PROPER" inflation. There is a reason for every tire there is a Load/Inflation chart.

Weigh your axles and add 5psi to what the chart recommends. This is per GY Tech support for when a person wants to use the brain GOD has given you instead of blindly airing to MAX sidewall pressure.

Im just curious.... if the chart is gospel, why go 5psi above what the chart recommends?

Mike


This is directly from GY Tech support. "When changing to a higher load range or wanting to have a better ride, better stopping traction and tread wear use the inflation chart and add 5psi".

They said to weigh each tire if possible as one side can weigh more than the other. The 5psi I assume is to compensate for one side weighing more than the other as most can't weigh each tire. They said "use the heaviest tire to determine inflation on each axle".
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

way2roll
Nomad III
Nomad III
Never ceases to amaze me how passionate people get about things like tire pressure. You'd think Rv'ers were discovering the cure for cancer.
2023 FR Sunseeker 2400B MBS

Walaby
Explorer II
Explorer II
I agree... it is load limit, and if you exceed the load by a pound you should go to the next higher rating. BUT, my interpretation of Cummins 12v98's post is even if I were at or below the appropriate rating, he recommends adding 5 PSI. Just strikes me odd that he (and others) are so adamant about following the chart, but then decide on their own to only take it as a recommendation and create their own chart (in their mind).

Just an observation, nothing more.

Mike
Im Mike Willoughby, and I approve this message.
2017 Ram 3500 CTD (aka FRAM)
2019 GrandDesign Reflection 367BHS

CapriRacer
Explorer II
Explorer II
Walaby wrote:
I'm just curious.... if the chart is gospel, why go 5psi above what the chart recommends?

Mike


Actually, the chart is a MINIMUM! Even says so! (Load Limit)
********************************************************************

CapriRacer

Visit my web site: www.BarrysTireTech.com

Walaby
Explorer II
Explorer II
time2roll wrote:
Walaby wrote:
Im just curious.... if the chart is gospel, why go 5psi above what the chart recommends?
Better to be 5 over than 5 under. Can lose some air naturally or through a slow leak.

I agree. I just really don't understand the mentality of "thou must obey the inflation charts", but then recommend 5 PSI over said inflation charts.


Mike
Im Mike Willoughby, and I approve this message.
2017 Ram 3500 CTD (aka FRAM)
2019 GrandDesign Reflection 367BHS

time2roll
Explorer II
Explorer II
Walaby wrote:
Im just curious.... if the chart is gospel, why go 5psi above what the chart recommends?
Better to be 5 over than 5 under. Can lose some air naturally or through a slow leak.

MFL
Nomad II
Nomad II
fj12ryder wrote:

"Jerry, the Fuzion came with 235/85-16, E-rated ST tires. Which were, I believe, rated for around 3,480 lbs., so the original tires were rated for about 21,000 lbs., still over the GVWR, and waaaay over my actual weight of 15,000 lbs. I actually considered going to LT tires when I had to replace those lousy ST tires. But the Sailun tires were cheaper than any of the other LT tires at the time.

I ran the OEM ST tires at 80 psi, max sidewall recommended pressure, and they failed in less than 2 years and 6,000 miles. The sidewalls were like tissue paper, they were so flimsy."

Thanks Howard! Having that extra axle sure changes capacity, and maybe lighter pin. Seems lots of changes in the RV tire world, some good, some bad.

Hope you are enjoying the new TH!

Jerry

Walaby
Explorer II
Explorer II
Cummins12V98 wrote:
Over/under MAX has nothing to do with "PROPER" inflation. There is a reason for every tire there is a Load/Inflation chart.

Weigh your axles and add 5psi to what the chart recommends. This is per GY Tech support for when a person wants to use the brain GOD has given you instead of blindly airing to MAX sidewall pressure.

Im just curious.... if the chart is gospel, why go 5psi above what the chart recommends?

Mike
Im Mike Willoughby, and I approve this message.
2017 Ram 3500 CTD (aka FRAM)
2019 GrandDesign Reflection 367BHS

fj12ryder
Explorer II
Explorer II
MFL wrote:
fj12ryder wrote:
If I ran my old trailer with tires at the max, I would have the capacity for nearly 24,000 lbs. on the triple axle. Having weighed the trailer, I knew I had barely 15,000 lbs. on those six tires. Absolutely no reason to run max pressure, and suffer the resultant rough ride.


Since a triple axle adds a lot of capacity to a trailer, I am just curious, if your previous trailer came with those tires rated to carry 24K. Did you upgrade from the OEM tires listed on the TH placard on the driver's side front?

Anyway, JIMNLIN, ^^^ and I are on the same page, when considering a RV trailer, outfitted with the proper ST tire.

Jerry
Jerry, the Fuzion came with 235/85-16, E-rated ST tires. Which were, I believe, rated for around 3,480 lbs., so the original tires were rated for about 21,000 lbs., still over the GVWR, and waaaay over my actual weight of 15,000 lbs. I actually considered going to LT tires when I had to replace those lousy ST tires. But the Sailun tires were cheaper than any of the other LT tires at the time.

I ran the OEM ST tires at 80 psi, max sidewall recommended pressure, and they failed in less than 2 years and 6,000 miles. The sidewalls were like tissue paper, they were so flimsy.
Howard and Peggy

"Don't Panic"

Cummins12V98
Explorer III
Explorer III
If one really cares they should know what weight is actually on their tires. But most are fine not knowing and blindly inflate to MAX.
2015 RAM LongHorn 3500 Dually CrewCab 4X4 CUMMINS/AISIN RearAir 385HP/865TQ 4:10's
37,800# GCVWR "Towing Beast"

"HeavyWeight" B&W RVK3600

2016 MobileSuites 39TKSB3 highly "Elited" In the stable

2007.5 Mobile Suites 36 SB3 29,000# Combined SOLD

GIB2
Explorer
Explorer
If original tires on trailer I would start with trailer manufacturer recommendation . I would then buy a $6.00 tire depth gauge . If the outsides wear first you need more air. If the center wear first you can reduce pressure a small amount and monitor till you get your magic pressure of wearing evenly.