Tire Pressure Q

[TCCamperNoob]

Hi All, I'm new to all this truck camper stuff. I recently went out on the road and had my tires filled to Ford/tire requirments cold (75 rear, 60 (front). All said and good, right? However, on the road my tires got up over the max pressure of 80psi, like 81-82. Is this normal or should I set cold temp lower? I'm using Wildpeal A/T3W tires LT275/70R18. Any advice would be appreciated. TIA

[Grit_dog]

phillyg wrote:
There's nothing wrong with using max 80psi for your E-rated tires. Set when cold, i.e., not driven on. All tires with get hotter and psi will go up as driven. No worries as that's factored in by tire engineers. The hottest I've ever seen my FW tires is 135 on a hot summer day. If you choose to go with F or G-rated tires, you'd still be limited by your axle rating, and you should first determine if your wheels can take 110psi.

Um, there aren’t any LT tires that are over 80psi. Any tires that are 110s are 19.5s or 22.5 for pickup truck applications.

[TCCamperNoob]

LOL You know you asked a good question when a bit of steam occurs in the thread...

[time2roll]

Kayteg1 wrote:

time2roll wrote:
Certainly never below the door sticker.
.

My 12' long camper was taking about 400 lb from front axle.
After having it weighted, I lowered from recommended sticker value, to tire manufacturer value for actual weight.
Per tire manufacturer, when my empty dually was showing 2800 lb (do I remember it right? ) on rear axle, I should drive with 30 psi.
Obviously for short periods of empty driving I did not play with it, but the results were pretty harsh, regardless Sulastic hangers.
Without the hangers I was afraid to drive empty over street covers.

Thank you for taking a selected snippet of my statement out of context.

I agree with your reduction of pressure for the specific case you have listed.

[TCCamperNoob]

Thanks for all the info.

What I learned here:

It may be better to fill my cold rear tires to max pressure of 80 PSI regardless of the door sticker.

Being over max pressure of 80 PSI while hot/driving is fine

My tires are not overheating at 5-8 psi over and even much higher pressure is still ok as long as I did not fill over the max psi while cold.

Some people recommend I get a degree in Tireology.

[JimK-NY]

BSWS19 wrote:
Setting the pressure at "cold" temperature makes sense to me but, do I need to compensate any in AZ when "cold" tire temps can be 80 to 90 degrees? I usually set mine about 5 psi less than recommended and still see highway temps of 100 to 110 degrees.

I lived a number of years in Phoenix where above 110 on a summer day was frequent. No, do not reduce the tire pressure. In fact consider higher pressure when the temps are high. Tires get really hot on pavement and high starting pressures reduce flex and help with tire life and safety. You probably notice a lot of RVs on the side of the road due to tire issues on hot days. Quite often the reason is low tire pressure.

[Grit_dog]

Agree, the door sticker is not a good source for proper pressure for the load.
Anyone who is hauling heavy, or even just driving, any vehicle, owes it to themselves to get just a little bit educated about tire load ratings and pressures based on load, driving style, weather and comfort.
Those that can’t, won’t or don’t, is why the mfg puts the door sticker on that basically gives you most or all of your OE trie load capacity or expected load without consideration for any of the above conditions I mentioned.
OP, on your srw truck, unless you’re hauling a lightweight popup camper, anything around 3klbs or above begets max rest pressure in most all common sizes of truck tires.

That pressure is also woefully too high when it comes to driving with no load and even more so in rain or snow.
Bottom line, learn what “your” pressure should be, not the generics mfgs recommendation. Also learn the basics of the ideal gas law. That will help one understand how it’s normal for the pressures to vary with temperature.

[Kayteg1]

time2roll wrote:
Certainly never below the door sticker.
.

My 12' long camper was taking about 400 lb from front axle.
After having it weighted, I lowered from recommended sticker value, to tire manufacturer value for actual weight.
Per tire manufacturer, when my empty dually was showing 2800 lb (do I remember it right? ) on rear axle, I should drive with 30 psi.
Obviously for short periods of empty driving I did not play with it, but the results were pretty harsh, regardless Sulastic hangers.
Without the hangers I was afraid to drive empty over street covers.

[phillyg]

There's nothing wrong with using max 80psi for your E-rated tires. Set when cold, i.e., not driven on. All tires with get hotter and psi will go up as driven. No worries as that's factored in by tire engineers. The hottest I've ever seen my FW tires is 135 on a hot summer day. If you choose to go with F or G-rated tires, you'd still be limited by your axle rating, and you should first determine if your wheels can take 110psi.

[time2roll]

TCCamperNoob wrote:
Hi All, I'm new to all this truck camper stuff. I recently went out on the road and had my tires filled to Ford/tire requirments cold (75 rear, 60 (front). All said and good, right? However, on the road my tires got up over the max pressure of 80psi, like 81-82. Is this normal or should I set cold temp lower? I'm using Wildpeal A/T3W tires LT275/70R18. Any advice would be appreciated. TIA

For about any truck camper you will want to run the rear at the sidewall max. Best to get on a scale to compare to the RGAWR and the tire inflation chart. Is that an oversize tire or OEM size?

[time2roll]

BSWS19 wrote:
Setting the pressure at "cold" temperature makes sense to me but, do I need to compensate any in AZ when "cold" tire temps can be 80 to 90 degrees? I usually set mine about 5 psi less than recommended and still see highway temps of 100 to 110 degrees.

Cold is in the morning, before you drive, and before the sun is on them. Does not matter where you are, what the temperature or elevation is. Frankly I recommend 5psi over the door sticker not to exceed sidewall max. Certainly never below the door sticker.

Heat kills the tire. Low pressure builds heat due to additional flexing of the sidewall. Best to error a bit to the high side... especially when it is hot. Yes the tire is made to withstand any increase in pressure due to the heat of the day, the hot road surface, and from driving.

[BSWS19]

Setting the pressure at "cold" temperature makes sense to me but, do I need to compensate any in AZ when "cold" tire temps can be 80 to 90 degrees? I usually set mine about 5 psi less than recommended and still see highway temps of 100 to 110 degrees.

[JimK-NY]

First, you should probably start out with your rear tires at the max 80 psi. That is measured with a cold tire, meaning the truck has been sitting in the shade for at least a few hours. You can drop down the front tire pressure to about 70 psi to improve the ride, but the camper weight is all on the rear tires and you need full pressure to achieve the maximum load capability. Under inflated tires will run hot, build excessive pressure and are prone to failure.

Next, expect the tire pressure to increase substantially under load especially at high speed on a hot day. If you start at 80 psi, you could easily see the pressure rise to about 90-95 psi. This is the way the tires are designed to operate and never reduce the pressure because it has built up during use. Again, the pressure should only be set with the tires cold. Even a few miles heading the gas station can throw off the setting.

[n0arp]

WNYBob wrote:
For carrying a TC you might want to go up in tires and get load rated D or E. They have stiffer sidewalls, therefore less flex and less heat.

80PSI is E. Might want to go up to F, G, or H... depending on what it is.

[WNYBob]

For carrying a TC you might want to go up in tires and get load rated D or E. They have stiffer sidewalls, therefore less flex and less heat.