Should you reduce pressure when driving on "Hot" Roads?

I got this question and thought that others might be wondering about the same topic.

Jim K asked

 Message: I will be traveling in the desert for the first time and I am
wondering if I should reduce the tire pressure before I go. The hot road will
increase the pressure and I am afraid of damaging my tires.
++++++++++++++++++++++


Hi Jim,

No you don't have to worry about hot roads.
IF you run the correct cold pressure


Now you didn't say if you have a standard RV trailer or a Motorhome so I will give you a summary for each application.


Trailers: You should set the Cold Inflation to the pressure on the tire sidewall. If you look at the sticker on the side of your trailer you should find the tire size, type, Load Range and pressure recommendation from the manufacturer. In almost all cases the recommended inflation is the inflation on the sidewall of the tires.
Have you confirmed you are not overloading any of your tires? Simply guessing or looking at the tires is not good enough you need to get the trailer on a scale and at a minimum get the total load on the tires. Now you can't assume the load is equally distributed side to side or axle to axle Measurements of thousands of trailers suggests you need to assume at least 53/47 to 55/45 split axle to axle and split side to side so you need to calculate the heaviest load based on an estimate of 27% to 30% of the total being on one of the 4 tires. A better method is to get individual tire loading. You can learn more HERE.


Motorhomes are a bit different than towables. Here you need to get the "corner" loading as the side to side difference is affected by the placement of things like generator, water tanks, refrigerators etc. The Front Rear loading is obviously different and for most motorhomes the number of tires on each axle is also different. You can use the information on your placard but a better method is to get the actual tire loading and then using Load/Inflation charts establish the MINIMUM cold inflation then add 10% to get your Cold Set inflation. THIS post has some info and a link in it.


Bottom Line

When tires are designed, we know that some vehicles will be driven on hot roads. Tires will normally run +20°F to +50° above ambient. You should run a TPMS to get warning of air leak due to puncture. If you are driving in the USA you should have no problems.
Most TPMS also have a high temperature warning that is set for 155°F to 160°F. If you get a warning at this temp but the pressure is above your set pressure by about 10%, simply slowing down should lower the temperature. If that doesn't work you can still stop for 10 minutes while you do a walk around to be sure nothing unusuall is going on.
If you are traveling to Saudi Arabia, the Sahara or Australian outback then we need to take some additional steps and precautions.

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