Nitrogen Filled Tyre Report – Believers and Deniers

Nitrogen Generator (membrane technology)

One of the most frequent queries we receive at the Campaign for Better Tyres is “Does Nitrogen filling of tyres work?”; fervent supporters of the program say yes and other folks say it is a con!

This Tyre industry promotion, in the words of Consumer Magazine and the Automobile Association “centre’s around the so-called benefits of having car tyres filled with nitrogen. Wondrous claims are often made that are either mis-leading or simply plain wrong….;”

Reduce tyre wear by up to 50%
Incorrect tyre inflation is the main factor with excessive tyre wear, not what you inflate the tyre with.

Nitrogen molecules are bigger than oxygen molecules, and hence your tyres will leak less and you will not need to check your tyres air pressure as often
Motorists pump “atmospheric air” into their cars tyres normally, which consists of 79% nitrogen. Consumer Magazine did a 12 month test of this, and had trouble measuring the difference between the two it was so small. And regardless of what tyres are filled with, their pressure must be checked at least monthly to detect leaks caused by punctures.

Nitrogen will improve the car’s ride
Nitrogen and “atmospheric air” have almost exactly the same compressibility, since atmospheric air is 79%  nitrogen.

Nitrogen will improve the car’s fuel economy
Correct tyre inflation (and regular checking) will have the bigger impact on fuel economy. As will the use of your right foot.

Nitrogen will reduce tyre rot and corrosion
Take a look at the outside of any car tyre, which is continuously exposed to “atmospheric air” and you won’t observe tyre rot. Any honest tyre shop can tell you that while environmental factors may cause a tyres external rubber to degrade, this never happens inside a tyre regardless of what it is pumped up with.

The tyre Nitrogen filling fad is driven by some tyre shop marketing plans and marketers of Nitrogen generating plants which are leased out to tyre shop operators contracted to buy a stipulated quantity of green valve caps each month. Sometimes consumers have to pay for nitrogen fills and other times the service may be free when the customer is buying a full set of tyres. Regardless, the consumer is getting nothing more than a set of green plastic caps!

A very small number of tyre shops may be offering Nitrogen fills from gas bottles supplied by reputable companies like BOC which will certainly be 99% pure. This gas is quite expensive and you can expect to pay for it. But most tyre shops get their Nitrogen from a Nitrogen generator; the process is quite simple. The generator is hooked up to the shops regular air compressor and the air flow is passed though a membrane with separates the Nitrogen from the air flow. At very best, these generators are harvesting Nitrogen up to 95% pure, or they could be pumping out 100% regular air.

These Nitrogen generators can be bought out of China for prices as low as $500.00 and are of wildly varying quality. After installation the machines are not calibrated and their nitrogen purity is not tested. The salient point here is that a faulty generator could be pumping 100% regular air into customers tyres, no one would ever know!

Sure, aircraft and heavy truck tyres benefit from being filled with Nitrogen, but authoritative organisations like the Automobile Association and Consumer advise these benefits to not extend to car, van and 4wd tyres. All the benefits claimed by Nitrogen filling believers can be achieved simply by keeping your vehicles tyre correctly inflated and going easy on the accelerator pedal.

Campaign for Better Tyres – Working for safer tyres and a safer motoring experience for Kiwi motorists.