RV 101® / RV Education 101®

Question: Can you tell me the correct pressure to inflate my RV tires to prior to taking a road trip? My travel trailer tires show a max psi of 70lbs on the tire’s sidewall. I can’t seem to get a straight answer from our local shops, and I want to make sure I don’t overheat or damage them. Thanks for any information you can provide.

Mark’s Answer:

This can be a bit confusing, but I’ll try and explain it. Tire manufacturers publish tire load and inflation tables for the tires they manufacture. In a perfect world you would know what the actual load placed on the tire is and you could go to the load and inflation tables for precise inflation pressures based on that load.

Of course things never work out that way. Since we know this isn’t always practical there are a couple methods to help determine tire inflation pressure. On the front left corner of the travel trailer you will find a Federal Certification Tag or label and a Tire and Loading Information label. These labels display information on tire inflation pressure, Gross Vehicle Weight Rating (GVWR) and Gross Axle Weight Rating (GAWR). The tire inflation you see on this label is based on the trailer’s designed load limits. If no additional weight is placed on tires this inflation pressure is accurate. The question is how much weight is placed on each individual tire? The only way to answer that is to have the RV weighed by individual tire position. If you can’t or don’t weigh the RV by individual tire position using the information on the certification label is the next best thing.

The inflation pressure molded into the sidewall of the tire is the maximum amount of air pressure you can ever inflate the tire to if a full load was placed on the tire. You can locate the maximum load range on the tires sidewall.

What this means is, if the trailer tires are not overloaded the inflation pressure (depending on actual weights) is somewhere between what is posted on the Federal Certification label and what is molded in the tire sidewall. In other words, in some cases it is possible to increase tire load capacity by increasing the inflation pressure in your tires, but you cannot exceed the maximum pressure specified on the sidewall of the tire. You can usually find tire manufacturer load and inflation tables on the internet.

It’s also important you use the same inflation pressure on both ends of each axle. If you weigh the RV and the tire loads are different on each axle end the load tables might require different inflation pressures. When this happens you need to redistribute the load if possible. If the load cannot be redistributed you would inflate both of the tires on that axle to the inflation pressure required for the tire with the heaviest load. But, keep in mind it cannot exceed the maximum tire pressure molded in the tires sidewall.

Here are a few general rules for tire inflation I like to use:

• Never pull the trailer with tires inflated to less pressure than required for the load placed on the tires.
•  Never pull the trailer with tires inflated to less pressure than what is on the Federal Certification tag, no matter what the load.
•  Never inflate your tires above the maximum pressure shown on the tires sidewalls.