Nitrogen tire inflation

Over the years, nitrogen tire inflation has been talked about, touted, researched, and challenged.

NASA, the US Military, commercial aircraft, Indy, and NASCAR teams all use nitrogen in their tires, which has proven to provide a more consistent tire pressure. Other benefits nitrogen inflation has been linked to include longer tire life, minimized service needs, enhanced safety, and fuel efficiency. With fuel costs and tire prices rising, nitrogen inflation has again sparked the interest of the over-the-road and off-road industries.

What do we know about nitrogen?

Nitrogen molecules are larger in size than those of air, which means it is slower to migrate out of a tire than air. Under the same circumstances, a tire filled with nitrogen will have slower inflation pressure loss rates than a tire filled with air. The longer a tire holds its proper tire pressure, the longer the benefits of a properly inflated tire will be seen, including extended tire life, lower fuel costs and ultimately, less downtime due to tire issues.

The various consequences of underinflated tires are well known: excessive wear, larger temperature fluctuations, higher rolling resistance and increased fuel costs.

With nitrogen, just as with air inflation systems, a tire maintenance program is still necessary, but due to nitrogen’s ability to hold tire pressure for a longer time interval, service time and labor costs decrease, as well as top-offs.

Another benefit to nitrogen is that it is a dry, inert gas. This may be obvious, but it is worth pointing out that removing oxygen from a tire and replacing it with nitrogen also means less damage to inner liners, steel belts and rims due to oxidation and condensation.

Avoiding another big bang

The Goodyear Off-Road Tire Maintenance Manual states that OEMs often recommend nitrogen tire inflation because “it helps to minimize the possibility of explosion due to excessive heat from external sources.”

Off-road vehicles are using nitrogen in tires more often to achieve consistent tire pressure and to prevent explosions. Nitrogen is not combustible and according to the Occupational Safety and Health Administration (OSHA), it has been issued a flammability rating of zero from the National Fire Protection Assn.

In a tire filled with air, the typical causes of inner tire ignition include excessive braking, dragging the brakes, welding on rims of mounted tires and—although less likely, but still a viable threat—lightning strikes. Switching to nitrogen tire inflation may not only be a wise financial decision, it may also prove to be safer.

A well-known study, Effects of Nitrogen Tire Inflation on Canadian Long-Haul Trucking, was presented in March of 2007. It was a government-funded, double blind study performed with a Canadian trucking company, Transport Canada. The company “showed a 3.3% improvement in fuel efficiency when comparing a driver-based tire maintenance program with a third-party tire maintenance program.” The company also “found a further improvement attributable to nitrogen tire inflation of 3.8% and an impressive 6.1% when comparing nitrogen inflation with a driver-based tire maintenance program.”

Just because tires are filled with nitrogen doesn’t mean the condition of the tires will automatically change. The key is that the tire will hold its proper tire pressure longer, which is why it can be expected to see benefits, such as a longer lifespan—possibly adding three to four retreads to the original tire—and lower fuel costs.

Down with downtime

A few years ago, a company out of Greenville, MI, was determined to get a handle on its fuel use and downtime issues, and decided to document its experience switching its fleet of over-the-road trucks to nitrogen. Pete Larsen, the president of Larsen Trucking, wrote, “In the first four months of 2006, our on-road tire repair expenses calculated by tire failure were $5,126.72 per month. In the same period for the first six months of 2007 [using nitrogen], the on-road tire repair expenses were $929.95 per month—an 82% reduction.”