Using Nitrogen in Car Tires Little More Than a Fad

With the price of gas skyrocketing out of control, people are looking into every possible option for conserving fuel and saving money. One way to help increase your mileage is to maintain proper tire inflation on your vehicle.

But there is one method of tire inflation being suggested that may be "sea monkeys" - it looks great in theory but the reality is somewhat disappointing. Many environmentalists and some tire manufacturers are encouraging consumers to move from inflating their car tires with compressed air to using nitrogen gas.

Nitrogen is an inert gas which means it does not react with other elements and that makes it safe to use. It also makes up about 78% of the air we breathe along with the 21% oxygen and 1% of other gases.

Proponents say that nitrogen-filled tires can improve your car's fuel economy. Unfortunately, the facts are less concrete. Nitrogen-filled tires really have no effect on your car's gas mileage except in that they don't lose their pressure over time as quickly as tires filled with compressed air might.

The average car tire inflated with compressed air loses about 2 pounds per square inch per month. There is science behind this claim, however.

Nitrogen molecules are larger than the oxygen molecules found in air. Even though we think of tires as being 'sealed,' they are actually somewhat permeable, so there are tiny 'gaps' in the material. The rubber and other composites in tire walls will expand and contract with age and climate making the gaps increase in size over time.

Because of these gaps in the tire's structure, the average automobile tire loses about 2 pounds per square inch (PSI) of ordinary air per month. Since the nitrogen molecules are too big to fit through the gaps, the tire filled with nitrogen will maintain its pressure more consistently.

The proponents of nitrogen inflation also say that nitrogen-filled tires will save you money over time. Again, nitrogen-filled tires maintain their air pressure longer and therefore they may wear more slowly under certain conditions and you wouldn't need to replace them as often. That is dependent of course on how you drive, what type of vehicle you own, and the environment where you live.

John Conn of Goodyear in Xenia, Ohio says, "It was a fad that's kind of going away." He states that the equipment required to distribute nitrogen is too costly for most independent tire retailers to purchase and operate. Conn says, "If you fill your tires with nitrogen, and they lose pressure, most places will just inflate them with air anyway."

Any quantity of air left inside a tire will permeate the tire faster than the nitrogen, so all of the air must be removed for nitrogen to be of any advantage at all. The only way to remove the air is by using a special vacuum pump that takes it out and replaces it with nitrogen.

In short, any advantage that may be gained by using nitrogen in your car tires is directly related to tire pressure and maintenance. Most of the evidence in support of nitrogen use, which is mainly anecdotal, suggests that standard maintenance on tires filled with regular air will achieve the same results as using nitrogen inflation.