tyre inflator

While this is not a new idea, race cars and aircraft have used nitrogen in tires for years, the concept as applied to the average mass-market automobile is highly controversial.

Proponents, mostly manufacturers of compressed nitrogen equipment, have been countered by naysayers. Scientific terminology has been bandied about by both sides in an area where real studies are difficult at best.

But the debate has centered on technical issues surrounding the benefits of nitrogen tire filling. The real question is just how much is this service worth.

Do the benefits of nitrogen in ordinary passenger car tires outweigh the cost?

Well, that depends on the cost.

When the idea of filling car tires with nitrogen was first introduced, tire retailers provided it as a free service for buyers. Some, notably Costco Wholesale, are still doing this.

But the idea soon morphed into a marketing fad. Tire stores discovered long ago that they could add charges for items that used to be standard, like balancing and valve stems.

So nitrogen filling was a perfect upselling item: invisible, intangible. Other than the snazzy green valve caps that accompany the nitrogen fill, how would a customer even know what was actually in their tires?

Starting with nominal charges of $3 per tire, the price was gradually raised to as much as $60 for four tires and a spare. Some offered "lifetime" free refills as justification for higher prices.

Car dealers noticed, and some jumped of the nitro-tire bandwagon. They put N-filled tires on the new-car additional dealer markup sticker, with a posted price of up to $300.

The dealer's cost is under $10, including labor.

Some dealers, at import stores with very high demand, are putting the eye-catching green valve stem caps on every car in inventory. Additional markup stickers for "VIN etch" or "spray-on fabric protectant" are a good reason to walk away from a dealership. But large additional markup for nitrogen filled tires is a reason to RUN!

The prices of nitrogen generators have been falling rapidly, to the well under-$10K area for small scale commercial applications. These machines can fill tires for as little as $.25.

This means the service could be provided by coin-operated machines similar to the air dispensers now in use.

Consumers would be better off learning to check tire pressure regularly, as NHTSA says less than 60% of American drivers do. Nitrogen may save gas, but it does not mean never having to check your tires

The majority of air pressure loss in tires is not through the sidewall. Road hazards, curb rubbing, and tire changing tools make small imperfections in rims, where poorly seated tire beads allow leaks. The rubber seal around valve stems is another culprit.

A cigarette-lighter 12-Volt compatible portable air compressor costs $10 at Wal-Mart, and an air pressure gauge as little as $3. Tire pressure monitoring systems are standard on new cars now, some are very accurate.

Nitrogen is OK as a "free" service that tire retailers and dealers can use to add value for their customers. Lifetime refills are a marketing ploy giving customers a reason to return for upselling of higher margin products and services.

And it is quite conceivable that a nominal fee of $5-6 per tire could be justified by fuel savings.