In a study reported in Rubber and Plastic News by David Coddington of Exxon Chemical Co. material from tires run for varying periods of road service and inflated with air was tested for tear strength. The laboratory findings; strength values are steadily decreased with increasing service mileage, leveling off at a value below 50% of original strength. In lab testing equivalent to less than 40,000 road miles, the relative strength of oxygen exposed tires declined to under 40% while the material from tires inflated with nitrogen held at over 80%.
Tire life to failure point in laboratory wheel tests confirmed more than twice the life for the nitrogen inflated tires. (Reference: “Factors in Tubeless Radial Tire Durability”, Rubber and Plastic News, August 1993.)
Nitrogen inflation has advantages in that tires will hold pressure longer using nitrogen. Nitrogen?s diffusion rate is 25% to 30% lower than air, significantly reducing tire pressure loss between inflation checks. Under inflated tires wear rate is increased to the point where a tire 10% under inflated will lose approximately 7% of it service life. On the other hand, properly inflated tires have less resistance to rolling. (References: Goodyear Application Bulletin #17 and Bandag Tread Guide, September 1995.)
Under inflated tires can cut fuel economy by as much as 2% per pound of pressure below the recommended level. Therefore a tire that is just five pounds below its setting will consume 10% more fuel. Additionally, tires with low air pressure are more sluggish in their response to steering input… compromising your vehicles handling.
Ever notice green valve stem caps on another cars tires? Those tires are filled most likely filled with nitrogen!