You may have noticed signs advertising nitrogen fills at tire stores around town and wondered why anyone would want or need to fill their tires with anything other than plain air. Nitrogen fill for tires is advertised as being better than air, but it also costs more and is more difficult to find than air. If you are curious about this type of tire filler, read on to learn more about nitrogen in tires.
The Benefits of Nitrogen
The main benefit of nitrogen over pure air is related to the size of its molecules, which are larger than air molecules alone and therefore less likely to leak out through the rubber of the tire. Since maintaining the correct air pressure can give you improved gas mileage, better road handling and make your tires last longer, the benefit is clear. As an added plus, nitrogen won't mix with water, so the problem of dry rot caused by moisture leakage is eliminated.
Checking for proper inflation on your tires often gets neglected, and even with tire pressure warning systems on most cars nowadays, the issue persists. Often, by the time we notice a problem or the warning lights up, it's too late and the damage may already have been done. The use of nitrogen means a more carefree approach, with one less thing to worry about as often since the air leaks out far more slowly than if filled with just plan air.
The Problems with Nitrogen
Nitrogen fills cost quite a bit more than the few cents you might pay at most gas stations; up to $6.00 per tire, depending on where you live. It's worth noting that the "plain" air that you get at most air stations for a few cents is already as much as 80% nitrogen. Nitrogen has not become popular enough for the fills to be widely available, but you can mix gases in the same tire and you can use a tire or two with different types percentages of air and nitrogen without harm or danger.
The air retention capabilities were tested by Consumer Reports and only a minimal improvement of 1.5 psi was found over plain air. This study concluded that the minor improvement in air retention did not justify the far higher cost of nitrogen over air.
Regardless of what you choose to fill your vehicle's tires, your best value can be had using the correct air pressure for your vehicle at all times. Not only does your vehicle get better gas mileage with the proper fill amount, but your braking ability is literally riding on proper inflation. The Car Talk experts recommend that you check your air pressure at least once a month.