When was the last time you checked your tires? Was it last month or last year? Tires are the most vulnerable part of any RV and fail more often than any other RV component.
Tires are required to withstand extreme changes in temperature, cushion the rig from potholes and bumps, and provide traction on wet or slippery road surfaces.
A simple pencil-type tire gauge is the most important tool you can own. To keep tires in prime condition, check and adjust the air pressure once a month (including the spare tire). Tire pressure should be checked first thing in the morning while the tires are cool. Tire pressure will rise as the day warms up or the sun beats down on the rubber.
Driving more than one mile will warm the tires and increase the air pressure. Changes in altitude also affect tire pressure. Don’t rely on the gauges found on the air hoses at service stations. These gauges are often dropped or run over and may not be accurate.
How do you know how much air to put in a tire? For a passenger car, the correct pressure, given in psi (pounds per square inch), can be found in the owner’s manual or right on the sidewall of the tire in tiny print. For a trailer, there may be a small plate affixed to the side of the trailer which lists the correct tire pressure or, again, the information can be found right on the tire. Car and trailer tires are usually run at maximum pressure.
For a motorhome or a tow vehicle, the correct tire pressure depends on the weight of the RV. The best way to weigh an RV is to have it weighed wheel by wheel (photo). The RV Safety Education Foundation does this at many RV rallies. The next best method is to weigh the rig axle by axle. This can be done at the large scales found at truck stops, sand and gravel pits, or interstate highway weigh stations. In some states, the scales at weigh stations are left on when the station is closed so you can weigh the rig yourself.
Once you know the weight carried by each tire of your rig, you will need to consult a tire chart to find the correct tire pressure for the load on the tire. Tire charts can be obtained from tire dealers or on the Internet at the Goodyear and RV Safety websites.
All tires on the same axle should be inflated to the same pressure even if the weight is slightly different on each tire. If you inflate your tires to more than 50 psi, ask for metal valve stems and metal valve caps to prevent air from leaking out through the valve.
What about the tire warranty?
At this point, you may be wondering why tire inflation and rig weight are so important. Underinflation or overloading is the main reason that RV tires fail. The sidewall of an underinflated tire will flex more than usual as it rolls down the road. Sidewall flexing creates heat in the tire, which directly leads to tread separation and blowouts.
The same thing happens to a tire that is loaded beyond its capacity. Tire manufacturers can tell if a tire has been underinflated or overloaded because the tire bead (the part of the tire that sits inside the wheel rim) will become deformed. When a tire is returned to the manufacturer for warranty purposes, it will be inspected for abnormalities in manufacturing or materials. If no abnormalities are found, and the tire bead is deformed, warranty coverage is usually denied.
Protect your investment
As you check the tire pressure each month, also look for bulges in the sidewall and odd-looking wear patterns such as scallops or grooves in the tread, worn down edges, or wear in the center of the tire. If you spot anything unusual, take the vehicle to a tire dealer to determine the cause. Replacing a damaged tire before it fails will save you a big headache down the road.