RV Tire Pressure 101
Tire pressure is important because when a tire fails, it will damage not only the surrounding fender skirts, but also the sidewall, wheel wells, and possibly the trim. That equates to a lot of money for repairs. You should never reduce your tire pressure below the required tire pressure for the load placed on the tire to get a softer ride on the road. Always make sure you have an accurate tire pressure gauge, and if your vehicle has dual rear wheels, make sure your gauge has an offset double head that can reach both the outer and inner valves.
Tires are designed to only carry a certain amount of weight based on their inflation. Each tire will have weight ratings printed on the sidewalls for the specific inflation pressure the tire should have to carry the maximum tire load rating. The suggested pressure will vary based on the tire configuration of your vehicle and the load placed on the tire.
Overinflated tires will wear out sooner. As you travel down the road, heat builds up in your tires, and tire pressure increases. Keep a digital tire gauge in your glove box and check the tires each time you stop for fuel.
Temperature and Altitude in RV Tires
When solids, liquids, and gasses get warmer, they expand. So as the air temperature rises, the tire pressure does too. You can estimate about 1 psi for every temperature change of 10 degrees Fahrenheit.
Altitude also affects tire pressure. The higher the altitude, the lower the atmospheric pressure, which is the ambient pressure you experience. (Gauge pressure is the pressure inside your tire.) So if you fill your tires to the recommended psi at or near sea level and then increase your altitude, you’ll likely gain 2 to 3 psi at the peak. However, as you reach higher elevations the ambient temperature drops, likely offsetting the psi increase.
Make sure you check your tires when you encounter environmental changes related to temperature and altitude. You can do so with a digital infrared thermometer.
What’s the Correct Pressure for RV Tires?
To determine the correct tire inflation pressure for your vehicle’s tire loading, check the manufacturer’s load inflation. You’ll find this information at tire dealers and on the manufacturer’s website.
Oxygen vs. Nitrogen in RV Tires
Perhaps you’ve seen green caps on tire valves at the campground. These signify that the rig is driving on nitrogen-filled tires. Some prefer to use nitrogen because it delivers a better fuel economy and a smoother ride.
The regular air in your tires is 21% oxygen and 78% nitrogen, with the remaining contents a mix of noble gases, carbon dioxide, and water vapor. Water vapor leads to moisture inside your tires, which can lead to corrosion of your rims. It can also cause your psi to change when the temperature changes, leading to over-inflation. That’s because the moisture retains heat and will expand when it gets hotter. Also, oxygen molecules will permeate the inner lining of your tire, leading to pressure loss and degradation.
Nitrogen, on the other hand, is a larger atom than oxygen and doesn‘t permeate the inner lining, leading to comparatively longer tire life. And when your tires are filled with nitrogen, they go through a purging and filling method that eliminates nearly all the moisture. This translates into steadier pressure over the long haul.
Whether nitrogen is right for you is a personal decision.