NITROGEN INFLATION: GOOD OR BAD FOR CAR TIRES?
Surf any automobile tire-related website these days and you will likely see something about nitrogen inflation. It is becoming a hot topic. There are inquiries concerning American Honda's position on this practice. When it comes to inflating automobile tires, ordinary, dry compressed air (which is about 80 percent nitrogen already) is the better choice. That is because it is more readily available and the benefits of using nitrogen simply do not appear to outweigh those of using compressed air.
The practice of inflating tires with nitrogen really isn't anything new, is has been around a long time. It is commonly used on aerospace vehicles, commercial and military aircraft, military vehicles, race cars and even heavy off-road construction equipment. Here's why:
- To meet rigid safety and performance specs, the required tire inflation pressures are often very high, especially in the aerospace industry. The tire inflation pressure for NASA's space shuttle, for instance, is 315 psi.
- Nitrogen is an inert gas; it does not combustor oxidize.
- The process used to compress nitrogen excludes water vapor. Water vapor can expand if the temperature climbs above 212 F degrees.
- Tires inflated with nitrogen leak slower over time than those inflated with compressed air.
Automobile tires, on the other hand, are subjected to an entirely different set of conditions. Here's why inflating tires with nitrogen offers no real advantages:
- Although tires inflated with nitrogen leak slower over time than thoise inflated with compressed air, they still leak and need to be reinflated to maintain proper pressure. If you can't find a place that offers nitrogen inflation -- and there aren't that many places that do offer it -- your only option left is to reinflate with compressed air. Doing that drops the nitrogen purity.
- Nitrogen offers no better protection against road hazards such as cuts and punctures. So no matter what you inflate your tires with, you still need to check the condition and pressure of the tires at least once a month, which is the recommendation in the owners manual.
- Trires that are inflated with compressed air and properly maintained offer the same fuel economy, tread wear and ride comfort as those inflated with nitrogen.
- Nitrogen for automobile tires is produced by nitrogen generators, which typically get about 95 percent purity. But, to actually get that level of purity into an automobile tire, you would have to deflate and inflate that tire with nitrogen several times. If you're not careful doing this repeated deflation and inflation process, the purity level winds up being closer to 90 percent, compared to the approximate 80 percent nitrogen already in compressed air. Because of this those claims of less pressure loss w2ith nitrogen aren't valid.
So, the bottom line is: Nitrogen is an ideal gas for inflating tires in aircraft, military vehicles, race cars and heavey off-road equipment, but when it comes to automobile tires, it offers no apparent advantages of ordinary, dry compressed air. So, just fill your tires with the air you breathe.
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