Tire pressure when the temperature changes 50 degrees

[larliebler]

Originally Posted by Old-Biscuit

Rough figures.........for each 10*F increase in Temp/1 psi increase in Press


Set tire pressures 'COLD'....not driven on for at least 4 hours and before SUN is shining DIRECTLY on tires






Curious.......
How frequent does anyone check daily driver vehicle tire pressures??


I checked truck/trailer EVERY Travel Day Morning....which was weekly/bi-monthly
Now that we aren't FTng.........check truck tires WHEN I suspect a tire might be low or when SHE asks "when was last time......"
Funny how 'we' make RV complicated/OCD and yet think nothing of our daily vehicles (Unless they are $$$ pits/clunkers---had a few of those)

Now you have me I'm worried I have OCD. LOL

[CIDE]

Relatively new to RVing and living out west (desolate), on my first trip I was possessed with my tire pressures, always wondering ??? On my return, my first purchase was a TPMS monitoring system (EEZ for the curious because they had a $90 off sale at the time I checked online).

Now I set my tire pressures before every trip, in the coolness of the morning and then rely on the TPMS to comfort my wandering mind. I check the pressures every morning before leaving, once or twice a day (like when I drop the right rear off the pavement ) and at then at the end of the day when filling out my day log. The TPMS brings so much comfort to my mind that I wouldn't consider traveling without one again.

I've been very lucky in that my tire pressures are very stable over time, varying only with temperature fluctuations. On my class C, I inflate the rear 16" tires to their max sidewall pressures of #80 and the fronts #5 less at #75.

[A Traveler]

I check the tire pressures every day before we hit the road.

The last time I added any air was...2014.

(Posted this on 1/15/2019)

[Frank Miller]

In my coach, the Federal Certification Tag indicates the maximum allowable steer and drive wheels cold tire pressures based on the vehicle's legal GROSS vehicle weight, not the actual weight the wheels are carrying (which should never be higher than the GVWR). But, how do you know what the weight is? You can spend the $11 at a CAT Scale to find out.

When cold inflated properly, the tire design will safely address the expected heat and pressure increases due to driving.

I set tire pressures based on the measured wheel weight and the tire manufacturers recommended inflation chart. Too much pressure and you can get a rough ride or exceed designed safe pressures. Too little pressure and you risk high tire temperature followed by a blowout. Although excessively high or low pressure can cause premature tire wear and increase stopping distance, the other safety factors are more critical.

I also use a Tire Pressure Monitoring System (TPMS). It makes it easy to glance at tire pressures without having to let any air out to manually check. In addition, the TPMS monitors all the tires, all of the time, including the ones on the Toad. It will also alarm if either the tire pressures or temperatures are abnormal.

One time when my coach was in storage the rear inner dual tire went flat due to a valve stem issue. I wouldn't have noticed and without the TPMS, wouldn't have known. Out on the highway the outer dual could have likely failed as well.

[F4Gary]

I use a tire pressure chart for that axle's weight, not the chart on the driver's wall.
I'm running a different load range tire now (G vs F).

[A Traveler]

Originally Posted by Frank Miller

...When cold inflated properly, the tire design will safely address the expected heat and pressure increases due to driving...

BINGO! That’s the best explanation I’ve yet seen as to why you should NOT adjust tire pressure based on temperature. It is also why I have not touched my tires since 2014.

Well said, Frank!

[beaverfever]

how often do you change your cars tire pressure? do you go out in the morning and then change them again for the evening commute. same thing applies for you rig.

[heathtx]

A couple of years ago, we left Dallas on a cold February morning, about 40F. Tire pressures were 98psi (proper for the coach weight). Six hours later we were in sunny west Texas (85F) and I got a high pressure alarm on the TPMS. Pressure was over 130psi. I stopped and let 10psi out to clear the alarm and the next morning when we left Van Horn the pressures were proper.

Maybe the high pressure alarm was set too conservatively, I don't think that's a bad thing.

[markarbogast]

Ok, here in Missouri during summer I have my tires at 95psi. But in the fall in the early morning the temp is low and tire pressure drops to about 75. After I’m on the road an hour and the tire warms up they are back on n the 90s again. If I inflated them to 95 in the morning they would way over inflated when the warm up. What to do?

[l1v3fr33ord1]

Originally Posted by Old-Biscuit

Set tire pressures 'COLD'....not driven on for at least 4 hours and before SUN is shining DIRECTLY on tires

...

I checked truck/trailer EVERY Travel Day Morning...

This is all the anyone needs to know to travel safely.

(I assume that "Old-Biscuit" adjusted tires pressures if needed after checking them.)

heathtx-

Increase your TPMS's high pressure alarm limit. And, don't release air from the tires after the RV has been underway.

[Monacoach]

Set your tires pressures at the coldest end of that huge temperature swing and then only check for leaks each time before you roll.

[CWSWine]

The labels behind the seat say 120 and when I weighted the coach Michlien tire chart said to use 100. I set my tire pressure for 105 and I check each morning before we depart. If the tire pressure is between 100 and 120 I good to go for that days travel if not I adjust. Before I leave on the trip I ensure all my tire pressures are set at 105 and before I leave to come home I will set the tire pressure to 105. That seems to work well for me and I'm not adjusting tire pressures at each overnight stay.

[Crasher]

For several years, I have set the pressures of all the tires @ 5-8 psi above the load chart for the weight they are carrying. I set them on a 60* morning at a 1000' elevation. This plan allows me to travel up to 11,000' altitude in temperatures ranging from 35* up to 100* without exceeding the sidewall max cold psi or dropping below the minimum to carry the load. No need to add or release pressure for 9-12 months. The only drawback is that the tires will wear the centers more than the outer edges due to being inflated slightly higher than the psi required for the load, but the tires will age out before they wear out, so it's not a big concern. A quick glance at the TPMS in the morning is all it takes to know all is well for the day. I see no reason to make it more complicated that this.

[Ray,IN]

Originally Posted by markarbogast

Ok, here in Missouri during summer I have my tires at 95psi. But in the fall in the early morning the temp is low and tire pressure drops to about 75. After I’m on the road an hour and the tire warms up they are back on n the 90s again. If I inflated them to 95 in the morning they would way over inflated when the warm up. What to do?

What did you do prior to buying a TPMS? To eliminate having to adjust tire pressures due to ambient temperatures, just use the Federal Tire Placard pressures. Tire mfgrs build tires to run at higher pressures when hot. Read Tireman9 blog for further knowledge.
Some state lower pressures make softer riding, Goodyear says any difference in ride is negligible.