Should Trailer Tires be Under Inflated when Traveling Through Desert Heat

Published 06/30/2016

Question:

I have the correct new rims rated @110 psi and new tires G235-80-16 also rated @110 psi on my 5ht wheel ~11,000 lbs. The tires are inflated to 110 psi cold @75F. When towing in the West Texas heat 105F, should I run the tires lower than 110 psi, because I know the heat and pressure will build significantly in these tires probably to 120 psi or more?

asked by: Ulli T

Expert Reply:

It is actually unlikely that the air pressure in the tires will increase by 10 psi even in the West Texas heat. You might see an increase of about 5 psi maximum. You would still not want to under inflate the tires though because that could actually be worse than having a slightly higher air pressure.

The rule of thumb on tire pressure change due to air temperature is 1 psi for every 10 degrees (Fahrenheit) in temperature change. In most parts of the United States the difference between average summer and winter temperatures is 50 degrees (Fahrenheit) which would be a 5 psi loss or gain. Which would be more of a problem on a trailer tire if it is 5 psi under-inflated.

I recommend checking the trailer's tire pressure in the morning before they are moved or heated up and set the maximum tire pressure at that time. Then, as the day will get hotter and the tire pressure will increase it will not be as much of a problem as if the tire pressure were lower with a load being put on them. When the temperature is reduced at night then the tire pressure would come down to the correct maximum tire pressure that was set that morning.

If you want to monitor the tire air pressure we do have the TireMinder Tire Pressure Monitoring System, # TM89FR, which is a system that will display the tire pressures.

expert reply by: Michael H