With over 600 posts here and with almost 300 on RVtravel.com I sometimes feel like a broken record. But when I see the same or similar questions raised almost every week on various RV Forums, I have to conclude that there are still many new owners who have not found the answers to the questions they have about RV tires.
So please bear with me if you already know the information I am posting today, and just consider it a refresher course.
1. How much air do you need in your RV tires? Most important, we need to protect against overloading our tires. With most RVs on the road having at least one tire or an axle in overload, this is a most basic need. For many years RVs have come with a Certification Label mandated by Federal Safety Regulations. The labels may look like these:
2. The labels have the VIN for the RV and the GAWR (Gross Axle Weight Rating), which is the Maximum you should ever have loaded on the axle. The label also has Tire Size and Load Range (aka Ply Rating), as well as the inflation needed by the tires to carry the load. On a Class A, the label is located near the driver’s left elbow. If you have a driver door in the motorhome, the labels are on the driver door jamb. If you have a trailer or 5th wheel, the labels are on the outside, driver side toward the front. While helping an RV owner a couple of weeks ago we discovered that the information on his label had been polished right off the sticker so he will need to contact his RV manufacturer to obtain new labels. I suggest that every RV owner capture a picture and keep copies in a couple of locations.
3. Inflation needs of the tire are determined by the load you place on the tires. Every RV should at least once stop at a truck stop scale and learn the actual load placed on their tires. In tests, it has been shown that essentially no one can look at or “kick” their tires and learn the correct inflation. If you want the facts, you need to get on a truck scale. Here is a video showing the BASICS. The more experienced folks will note that the trailer in this case only got the total for both axles, which is OK for learning the basics. There are other posts here that cover the advantages of “4-corner weights” but I want you to at least get the basics. Here is my latest weight sheet.
4. If you want to confirm your MINIMUM inflation required, you can just confirm your actual axle weights are lower than the GAWR numbers on your Certification label, or you can consult a Load Inflation table like this.
5. I have a number of posts on how to use the tables, but as long as your weights are lower than the Certification Label GAWR you can use the inflation numbers on that label.
6. You should check and set your inflation when tires are at Ambient temperature, i.e., temperature in the shade. This means before the tire has been driven on or in direct sunlight for the prior two hours.
7. You should have and use a tire pressure monitoring system (TPMS) to warn of air loss due to cuts or punctures. There are a number of posts here on testing and programming your TPMS and how to care for your tires.