 |
 |
 |
|
|
Why Nitrogen?
Correct inflation is highly significant when considering tire life and performance. It is not always possible to look at a tire and detect under-inflation. However, under-inflation can cause many tire-related problems.
As inflation pressure largely determines a tires load capacity, under-inflation results in an overloaded tire.
An under-inflated tire operates at high deflection, resulting in increased drag and mechanical flexing of the tire. This often leads to excessive heat buildup, and may result in catastrophic tire failure.
Experts in the tire industry indicate that oxidative aging is one of the primary causes of decreased tire life. Oxidative aging is caused by the diffusion of oxygen from the pressurized air cavity of the tire to the outside atmosphere. Tests have shown that if tires are inflated with nitrogen, there is a significant reduction in tire failure.
Air is about 1/5 Oxygen, and oxygen, especially at high pressures and temperatures, is a very reactive element.
When oxygen reacts with things, the process is called oxidation. When oxidation is extremely rapid, it's called "burning".
That's one reason nitrogen is used in off-highway and aircraft tires. These tires run so hot they can actually catch on fire. Nitrogen doesn't support combustion, so nitrogen-filled tires don't add fuel to the flames. And nitrogen helps prevent slower forms of oxidation also.
Why did race cars, military and off-road vehicles switch to Nitrogen?
The biggest advantages - improved tire life
Nitrogen prevents other types of corrosion as well
Oxygen and moisture corrodes aluminum and steel wheels. Oxygen also reacts with rubber, another type of "corrosion". When this corrosion starts, the small particles break off and form rust and dust, which can clog vavle cores, causing them to leak. The rough surfaces created from the corrosive action on the wheels leads to tire beads that don't seal properly, causing additional leaks .
Oxygen also ages the inner liner, the thin layer of rubber inside the tire whose function is to keep air away from the carcass. As the inner liner ages, more and more air molecules can pass through it, causing more pressure losses. These pressure losses in a truck tire can average 2 psi a month as a result of the air passing through the sidewalls. As it passes through the rubber, the oxygen can also corrode the steel cords, causing them to rust too.
How does Nitrogen help?
While both nitrogen and oxygen can permeate rubber, nitrogen does it much more slowly. It might take 6 months to lose 2 psi with nitrogen, compared to just a month with air. And nitrogen is far less reactive. It doesn't cause rust or corrosion on steel or aluminum, and it doesn't degrade rubber. Wheel surfaces stay smooth and clean, rubber remains supple and resilient.
Nitrogen also will not degrade the rubber seal in the valve core which extends valve core life and helps prevents core leaks.
Small bits of dust and debris as a byproduct of oxidative corrosion to the wheels and alloy rims can lodge in the valve core seat, causing air leaks.
Any other reasons for using Nitrogen?
Water!! The air around us is full of water vapor. Compressing air concentrates the water in it. Draining the water from your compressor tank daily helps, but unless you have a really efficient air dryer system, chances are that there's a lot of water in your compressed air.
When you compress air, it takes up much less volume, but the percentage of water by volume is greatly increased.
...and what harm does this moisture cause?
Water vapor in compressed air acts as a catalyst, accelerating rust and corrosion. Water vapor also absorbs and holds heat. And when it changes from liquid to vapor, water expands tremendously in volume.
As a result, tires inflated with wet air tend to run hotter and fluctuate in pressure more. That's one of the reasons why racing tires, where fractions of a psi can radically change the handling characteristics, are inflated with dry nitrogen.
Some Web Info
www.goodyear.com
www.sunliner.com/nitrogen
www.macstire.com
www.msnbc.msn.com
www.tirefactory.net
|
|
|
 |
 |
