The Mudcat Café TM
Thread #96401   Message #1885011
Posted By: JohnInKansas
13-Nov-06 - 05:23 PM
Thread Name: BS: Nitrogen in your Car Tires? Bull Or Not
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
Nitrogen is used in aircraft tires and pneumatic struts because it's necessary to have "very dry" gas at altitude. You can buy a bottle of nitrogen with certified and confirmable moisture content. If you use air you generally have to compress it yourself, condense out the gross moisture, filter the bugs and beetles out, centrifuge out the main part of the remaining moistures and usually run it through an absorber to get the rest of the moisture. Complicated and costly.

Nitrogen is cheaper there, and much more convenient.

Racers use bottled nitrogen largely for the same reasons - because it's much more convenient than dragging a compressor around and more consistent in quality.

Additional "benefits" claimed by either of the above are "mostly mythical."

For the average user, maintaining proper tire pressures is vastly more important than what gas is used, and air is a lot cheaper and much more convenient. You drive up to somebody else's pump and adjust on a regular basis. Consistent maintenance will do a lot more for you than "cheap tricks."

Letting your "installer" fill your tires with nitrogen won't eliminate the need to check them regularly and won't reduce the leakage or changes in pressure due to seasonal temperature changes that result in the need to "add air." The "reduced oxidation" touted by some is immaterial for most users, since the most common deterioration is "sidewall rot" from the outside in.

(Especially with newer tires, and with lighter vehicles, the sidewalls typically rot to unsafe condition well before the tread wears out. Keep it in mind when checking them.)

For most users, nitrogen filled tires ARE BULLSHIT.

One marginally possible use for them might be in an area where very cold winters, with large and sudden seasonal swings in temperature, and very high summer humidity, might cause some "startup thump" due to freezing of even small amounts of moisture. Humid air pumped in during the summer can have quite a bit of moisture that rarely will condense to significant amounts when the temperature drops. This might be a problem if you regularly commute between Panama City and Nome, but then you'll need to carry your own nitrogen bottle for enroute adjustments.

If you "seasonally adjust" by adding air compressed during the season at hand when the weather cools, the air you put in will usually be dry enough due to condensation in the storage tank (unless the tank is indoors and draws it's intake from the sauna at your fillup station) to take care of it. The effect is usually less than the "cold set" of the rubber itself, and it usually goes away after a short drive anyway, so most people needn't worry about it.

In the US, automakers generally recommend lower pressures than the tire "rated pressure" in order to provide a "smoother ride." For most vehicles you can safely check the rated pressure stamped on the side of the tire and inflate to that value. A higher pressure, within the limits of the tire construction, generally will give a little better fuel economy and sometimes better tread wear. A very few vehicles, particularly the high cg "UTEs," are a bit finicky about having exactly the pressure specified by the vehicle manufacturer to get "normal handling." Even for these rare birds, underinflation is much more dangerous than overinflation. Higher inflation pressures, up to the tire rating, may be needed to realize the "maximum gross weight" limits stamped on your door pillar, so investigate if you usually carry a lot of junk stuff around.

For most of us, nitrogen is spelled M.A.R.K.E.T.I.N.G. - because it's something extra they can "offer" to get a bit more of your money, and it's easy to spout "anectdotal proof" that the gullible among us really need it.

John