I have heard that filling tires with nitrogen rather than air is becoming a common practice in the replacement tire market and that the National Highway Traffic Safety Administration (NHTSA) has seen reduced aging of tires filled with nitrogen. Is Nitrogen worth the price. Has there ever been a study that substantiates some of this?
Yes, Consumer Reports wanted to find out if nitrogen is worth the price, so they purchased a Nitrogen Inflation System and checked out how well the inflation held up over a one year period. They evaluated pairs of 31 tire models of H- and V-speed rated, all-season tires used in our tread wear test from 2006. They filled one tire per model with air and the other with nitrogen. The test was quite simple: fill and set the inflation pressure at room temperature to 30 psi (pounds per square inch); set the tire outdoors for one year; and then recheck the inflation pressure at room temperature after a one year period.
The tires were filled and deflated three times with nitrogen to purge the air out of the tire cavity. They also used an oxygen analyzer to be sure we had 95-percent nitrogen purity in the tire--the claimed purity limit of our nitrogen system, which generates nitrogen gas from ambient air.
The test started on September 20, 2006 and the final measurements were taken on September 20, 2007. The results show nitrogen does reduce pressure loss over time, but the reduction is only a 1.3 psi difference from air-filled tires. The average loss of air-filled tires was just 3.5 psi from the initial 30 pressure setting. Nitrogen-filled tires lost an average of 2.2 psi from the initial 30 psi setting. More important, all tires lost air pressure regardless of the inflation medium, so consumers should check their tires' air pressure routinely. No evaluation was done to assess the aging claim.
Bottom line: Overall, consumers can use nitrogen and might enjoy the slight improvement in air retention provided, but it's not a substitute for regular inflation checks.
Article posted from Consumerreports.org
