TORONTO — There’s nothing magical about nitrogen’s ability to prolong tire life. It won’t restore the original luster to the innards of your tires, it doesn’t smell better, and neither will it save the environment.

But using nitrogen rather than compressed air to inflate tires has two principle advantages. First, its permeation rate is 35 percent slower than air, resulting in tires that stay properly inflated longer, keeping tires running cooler, improving tread life, minimizing sidewall flex, and overall, lowering the rate of pressure-induced blowouts.

Second, nitrogen is dry and contains no moisture. It’s inert so rust cannot form since there is neither oxygen nor moisture present to cause oxidation of the wheel.

Nitrogen tires fail less frequently and offer 48 percent more
miles before quitting, according to a definitive study on the subject

Until recently, there has not been a convenient, reliable, economic means of distributing nitrogen to inflate tires. In the past, nitrogen would be provided in large liquid tankers transferring the nitrogen to large on-site storage vessels, or it was delivered in high-pressure cylinders.

But these days technologies have been developed for on-site use that purifies regular compressed air into high purity nitrogen.

There are two types of nitrogen generating systems: membrane generators and pressure swing adsorber generators (PSA). Both produce 98-to-99-percent pure nitrogen, but the PSA generators are typically rated for less than 90 psi output — a little weak for heavy-duty truck applications, but suitable for light- and medium-duty trucks. The output of membrane generators, however, is equal to the input pressure.

The definitive study on nitrogen-filled truck tires, “Million Mile Truck Tires — Available Today” was conducted in 1986 by Lawrence Sperberg and clearly demonstrates the advantages of using nitrogen for truck tire inflation.

Sperberg found in a study involving 54 new and 44 used tires running 7,345,497 tire miles in drive-axle service, that the nitrogen-filled tires ran 26 percent more miles before tread wear demanded replacement.

In the case of the failed tires, a smaller percent of nitrogen tires failed physically (30 percent vs 57 percent), and they gave 48 percent more miles before failing than did the air tires.

More recent testing conducted by Drexan Corp., the Canadian distributors of Parker Hannifin’s Tire$aver system, with a major Winnipeg-based truckload fleet showed similar results.

According to Konrad Mech, vice-president of Drexan Corp., fleets that closely monitor tire condition and tire-related maintenance costs could easily see a full payback on a nitrogen generator system within three to six months.

“The more rigorous the maintenance program, the clearer the payback is,” says Mech.

The system Mech recommends to medium-sized fleets (300 power units and 500-1000 trailers) represents a $12,300 investment. It costs about $1,000 to install and requires about $600 in annual maintenance.

There are no ongoing costs other than what a shop would normally incur in the operation of the compressors, labor, etc. The improved tread wear, longer casing life, increased retreadability, and lower failure rate, all attributable to nitrogen fills, will quickly become apparent to a fleet that watches its numbers closely.”