Filling tires with nitrogen isn't a new thing. For many years nitrogen-filled tires have been successfully used for specific reasons by the US military, the FAA, and heavy highway equipment operators. NASCAR fans know that the drivers use nitrogen-filled tires because they stay cooler and maintain consistent tire pressure. Now, filling tires with nitrogen instead of air is becoming a mainstream practice that tire retailers tout as a money-saving alternative for all vehicles, including RVs.
Nitrogen-filled Tires Maintain Consistent Pressure
Filling the gas tank and replacing tires are two of the major expenses for RV owners. Anything that can be done to extend the tread life of the tires and improve gas mileage is worth taking a look at. You already know that one of the biggest enemies of tire tread and good gas mileage is under-inflation or inconsistent tire pressure that creates uneven and premature wear on the tire. As a general rule of thumb, the life of a tire can be decreased by around ten percent for every ten percent that it is under-inflated. This may not seem like much, but as a general example, and ignoring all other factors such as alignment, etc., a tire that is rated for 80,000 miles and requires inflation of 32 psi will only be good for around 72,000 miles if inflated to only 29 psi. Simply put, with the stated scenario you're losing out on about 8,000 miles of tread life due to under-inflation!
Proponents of nitrogen-filled tires say that inconsistent and under-inflation is minimized by filling tires with nitrogen because air leaks from tires three to four times faster than nitrogen does. This means that under-inflation is more likely to occur and occur more frequently. In September 2006 through September 2007, Consumer Reports (http://blogs.consumerreports.org) conducted testing in which they evaluated pairs of 31 tire models of H- and V- speed rated, all season tires used in a tread wear test from 2006. They filled one of each model tire with oxygen, and one of each model tire with nitrogen. The inflation pressure was at room temperature to 30 psi. The tires were put outside for a year, after which the inflation pressure was checked at room temperature. The results showed that the nitrogen did reduce pressure loss at a reduction of 1.3 psi difference from the tires that were filled with air.
Proponents of nitrogen-filled tires also say that oxygen corrodes aluminum and steel wheels, creating dust and rust that can clog tire valve stems that may leak after becoming clogged, resulting in under-inflated tires. Additionally, if the rust and dust migrates to the wheel flanges and tire beads, they may not seal properly and may leak, creating under-inflation.
Maintaining proper tire pressure is critical for safety, handling, and optimum fuel economy. When tires become heated, the tire pressure can fluctuate because of the moisture content in the compressed air in the tires. Nitrogen is a dry gas, and therefore there is no moisture to heat up and expand and create significant pressure fluctuations. If you're a road warrior, safety is always on your mind, and you can appreciate even a slight improvement in gas mileage. According to the U.S. Department of Energy, gas mileage can be improved by 3.3 percent when tires are kept properly inflated. If you travel several hundred miles per year, you can see that a 3.3 percent improvement in gas mileage can save you a lot of money at the gas pump!
In a November 2004 article by Lisa Aichlmayr for TireBusiness.com, D.D. Coley, President of Consumer Tire Inc. in Mentor, Ohio, stated that her company had filled motor home tires with nitrogen and the users reported much more stable tire pressure levels. Several reports state that nitrogen-filled tires maintain proper inflation pressure for about three to four times longer than air-filled tires. This can help stop the annoying tire pressure monitoring system (TPMS) alerts created by inconsistencies in tire pressure. This can also mean peace of mind for those who forget to frequently check their RV tire pressure, but tire manufacturers warn that tire pressure should be checked frequently, whether air or nitrogen is used to inflate the tires.
What Does It Cost?
Regular RV tires can be filled with nitrogen, so there are no 'special' tires to purchase. Some tire retailers look at providing nitrogen for tire inflation as a marketing tool, a bonus provided in exchange for customer loyalty. In order to recuperate some of the expense of purchasing a nitrogen generating system, some tire retailers charge a fee to will fill tires that were not purchased at their store. Others won't fill the tires with nitrogen or top off the tire pressure unless you've purchased the tires from them. Many retailers, such as Costco Wholesale, sell tires that are nitrogen-filled at no additional charge. The cost of having the tires filled varies, depending on the tire size and pressure. The average cost seems to be anywhere from three dollars to ten dollars or more per tire. If you put a lot of miles on your RV, the savings on gas may offset the expense of having your tires filled with nitrogen.
At this point, you may not be able to drive up to just any gas station and expect to find nitrogen to top off your tire pressure. The best place to find nitrogen is at large retailers with tire departments or at tire stores. You can locate places in the United States and Canada that fill tires with nitrogen with a locater tool at GetNitrogen.org (http://www.getnitrogen.org/). If your tire pressure is low and you can't find a place to get nitrogen near you, it's safe and non-problematic to top off the tire pressure with air. When you get to the next available nitrogen or get home, you can have the tires purged of air and refilled with nitrogen.
Gimmick or Golden?
There are those who are definitely exaggerating about the benefits of nitrogen-filled tires in order to sell their products. On the other end of the spectrum, critics say that since air is 78% nitrogen and the 'pure' nitrogen used in tires is about 95% nitrogen, there is not enough difference to warrant filling tires with nitrogen instead of air. In some cases, getting your tires filled with nitrogen does cost you. But the simple facts are:
- Nitrogen maintains proper inflation pressures for up to four times longer than air.
- Nitrogen is a dry gas and does prevent moisture in compressed air from heating and expanding, and creating inflation inconsistencies.
- Preventing inflation inconsistencies increases gas mileage by up to 3.3 percent. Saving gas is good for the traveler's wallet and for the environment.
- Preventing inflation inconsistencies is safer and provides better handling of the RV.
- Proper inflation extends the tread life of tires.
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