It’s National Tire Safety Week, so this is a good time to discuss the topic of RV tires. Although I am a professional engineer, my area of expertise is not specifically in materials or road safety. I leave the topic of tire theory to Walter Cannon, executive director of the RV Safety Education Foundation (http://www.rvsafety.com). Walter has written many articles and produced many videos on RV tires and safety, and I highly recommend them to anybody who wishes to further educate themselves. This two-part article serves as a general overview of the basics of tires in order that RV owners may understand tire types, inflation pressure, and general use. In part one of this series, I will discuss the important topics of inflation pressure and loading.
Many RV drivers believe that it is appropriate to simply air the tires to the inflation pressure shown on the tire or vehicle ID plate. This is a dodgy oversimplification, as the listed pressure is the maximum design inflation pressure for the tire, and may not be a safe pressure for the RV load. The correct way to determine proper air pressure is to weigh the RV at each tire position and note the highest weight borne by each axle. Most tire manufacturers post recommended inflation pressures based on weight on their websites. Use your data to determine the correct inflation pressure for each axle as determined from the manufacturer tables.
Check the air pressure in each tire at least once a month, before each trip, and each morning before you drive. Tire pressure should be checked cold, as pressure ratings have been determined with typical running heat/pressure build-up in mind. Remember to check the air pressures of the inside tires on dual wheels and inflate all duallies on the same axle to the same pressure. Ensure the valves and caps are free of dirt and moisture.
Most people recognize the risks of overinflation, such as chance of blowout and poor tread wear. However, underinflation also carries significant hazards. Underinflation presents a higher chance of damage due to road hazards, reduces casing durability and fuel economy, and results in uneven or irregular tire wear. Additionally, Severe or prolonged underinflation brings about an increased risk of tread separation.
RV owners sometimes lower tire pressure in an attempt to create a smoother ride. This is not only dangerous, it’s relatively ineffective, as the difference in ride quality is not significant. When minimum recommended inflation pressures are not maintained, durability and optimum operating conditions for the tires are compromised. Therefore, tire inflation pressure should always meet at least the minimum guidelines for vehicle weight. It’s important to note that if the pressure in any tire drops by more than 20% of recommended inflation pressure, the tire should be professionally inspected before air is added. Personal injury may result from the tire separating from the rim while under pressure. A professional tire shop will use a cage to inflate the tire.
Overloading tires can have serious consequences for passengers and the RV. Too much weight causes stress on the suspension system, brake failure, shock absorber damage, handling and steering problems, irregular tire wear, and possible tire failure. Excessive load or underinflation can lead to an excessive amount of heat buildup, possibly resulting in tire failure. If you find that your tires cannot handle the load, lighten the load or install tires with a higher carrying capacity. Remember to consult your owner’s manual, tire retailer, or RV manufacturer for information concerning selection and installation of new tires.
In next week’s article, I will discuss RV tire types.
About the Author:
Steve Froese, an avid RV owner, traveler, and Coach-Net member since 2013, is the principal of “A Word to the Wise Technical Communications”, a published RV author, certified RV technician, and licensed Professional Engineer. He frequently collaborates with the “RV Doctor”, Gary Bunzer, and has worked with the RVIA/RVDA as a technical and training writer and consultant. Professionally, he works as a quality engineer and musician. Watch for more of Steve’s work in upcoming Coach-Net publications.
Karl P. UT~ “Kurt from Quality Tire was exceptional. He came and pulled both sets of back tires. The inside tires on both sides of our motor home had 0 pressure. Both Valve stems had been damaged for some reason. He replaced the valve stems on both tires, checked and filled all 6 tires to correct pressure. He was a pleasant and pleasurable person to work with. We were called by Coach-Net several times to make sure everything went as it was supposed to. Thank you to all the Coach-Net Representatives and to Kurt from Quality tire. It took something that was a pain and made it a pleasure.”