Nitrogen Instead of Air in Tires

<div class='quotetop'>QUOTE(Betelgeuse @ May 4 2006, 07:44 PM) [snapback]250036[/snapback]</div>

To increase the life of the optical coating. All good lenses for telescopes and cameras have coated lense - the coatings are for various purposes - from chromatic corrections to filtering. By filling the inner inter-lense chambers with nitorgen or other inert gases wil prevent oxidation of these coating - or worse - fungus growth on organically base coating material.

 

The fact that costco is giving it away for free indicates to me that there is some value to the Nitrogen... Costco is pretty good about spending money on things that matter (e.g. employee wages) rather than fluff. I'm guessing they probably negotiated a great deal on the nitrogen generating equipment so it doesn't cost them much to use it rather than air.

And the fact that is is used in racing and airplanes shows that there is some benefit.

But all the scientists make good arguments that the benefits are quite small.

So my take is that it's not worth spending any extra time or money to get your tires filled with Nitrogen, but if you happen to get it for free, you should be happy that you might be getting some minor benefits.

 

Some of the folks I race with use Nitrogen for their tires. The explanation I have heard is that most air compressor tanks have a lot of water vapor in them, and when the high humidity air is used in tires that run hot (typically over 200 degrees on the race track), the water vapor tends to expand much more than the air itself, causing unpredictable air pressure changes. Using a dry gas of predictable mixture (and Nitrogen is the most convenient and cheapest) gives more predictable changes in air pressure. I spent a season using Nitrogen in my race car tires and noticed a small reduction in pressure change at best. I wouldn't ever bother with it in my street cars. What's going on inside the tire is way less destructive than what's going on outside the tire, so I don't think it could possible lengthen tire life.

 

<div class='quotetop'>QUOTE(narf @ May 5 2006, 02:07 PM) [snapback]250348[/snapback]</div>

Water vapor expands and contracts with temperature at the same rate as any other gas.
Unless you are boiling liquid water in your tires, water vapor is not going to cause any difference in your tire pressure.

 

<div class='quotetop'>QUOTE(kirbinster @ May 5 2006, 09:58 AM) [snapback]250288[/snapback]</div>

So much for my recalling college chemistry. I stand corrected.

But I still figure that plain old air is good enough for the tires...

 

<div class='quotetop'>QUOTE(Kiloran @ May 5 2006, 12:37 PM) [snapback]250372[/snapback]</div>

With tire temps at over 200 degrees, and brake rotor temps at 800 degrees plus, it's possible to boil water that may have condensed out of the air. Remember we are talking racing, not street use.

 

Up til a few years ago, I raced Late Model stockcars for about 15 years. We always used nitrogen in the tires, because the regular air from the compressor, expanded too much with heat, which would change the tire stagger or tire cicumfrence. With stockcars, tire stagger is everything. The tires still grow with nitrogen, but not as much. I can see no advantage whatsover by using nitrogen on a steetcar.

 

As I was filling my tires the other day at a gas station, I noticed water droplets spitting out of the filler valve from the compressor. So I believe that normal compressors have problems with condensation, leading to water getting inside the tires.

Perhaps the nitrogen compressors somehow avoid the water vapor. If so maybe they should just call them dry compressors.

It makes sense that water in the tires could boil at high temps, leading to changes in pressure. Whether that is a problem obviously depends on how much water is in the tires and how often we get up to those high temperatures. My sense is it's not a big deal.

After all, if it were a miracle cure for mileage the auto companies would deliver their vehicles with nitrogen filled tires in order to get their fleet mileage down.

 

<div class='quotetop'>QUOTE(qbee42 @ May 5 2006, 10:33 AM) [snapback]250316[/snapback]</div>

I would suggest we stick the valve stem into the appropriate orifice and fill each tire with whatever gas you can provide. If you laugh perhaps that might be laughing gas.
Gary

 

It's the moisture in normal unfiltered air from a compressor that is the problem; if you own an air compressor with a tank, you know that you have to open up the valve on the bottom every so often and drain the water out of the tank. If you don't drain it, a significant amount of water will be present in any air that comes out of the tank, which can damage air tools, cause problems in tires, etc. In the very worst case, it could rust out the air compressor tank eventually causing explosive failure.. Good shops always have oil and water separators on their compressor outlets, and the best shops also pass the air through a dessicant dryer and particulate filter so that you get only clean, dry air coming out the end of the hose. Dessicant driers are getting cheap enough these days that I even have one for the small compressor in my garage, which I use among other things, for filling up my tires.. Dry air will behave indistinguishably from dry nitrogen in tires..

Even if you don't have the scientific background to understand the ideal gas law, if you actually stop and think about the claims, it's very obvious that they are flawed at best- if the claims that nitrogen doesn't leak vs. oxygen, then what would happen is that over time, the air in your tires would increase in nitrogen concentration as all the oxygen leaks out, and eventually it would all be nitrogen anyways..

As for assuming benefits because Costco uses it- yes, the benefit is entirely to Costco- it's a cheap gimmick that they can offer with a plausible sounding explanation- if even half the people believe that this is true and that Costco is offering them a "valuable bonus" for free, they'll be more likely to bring in their tires for service at Costco vs. some other place.. My feeling is that if they're giving it away for free, and it doesn't do any harm and most importantly, their service is good, then it doesn't hurt to fill with nitrogen, but I certainly wouldn't pay anything extra for it.

I'll reiterate that nitrogen offers *no* benefits vs. dry air from a properly drained and filtered compressor of a professional tire service establishment, but it *may* be better than the air from the pump of the corner gas station where there's no filter and the compressor may not have been drained in months..

 

I put nitrogen in my tires for two reasons.

1. The cool nitro caps they put on afterwards.
2. Any goodyear can top off the air, with accurate gauges (when needed), instead of going to a gas station.

 

<div class='quotetop'>QUOTE(Tony Ducks @ May 25 2006, 04:20 PM) [snapback]261034[/snapback]</div>

I use air instead of nitrogen because:

1. i can use whatever caps I want
2. I can top off the air whenever I want at home

 

<div class='quotetop'>QUOTE(SW03ES @ May 25 2006, 04:25 PM) [snapback]261037[/snapback]</div>

why do you want to get out of the car??
Let them do the work.

 

1. Is this true?
2. If so, why do they do it?

References, please. The posted arguments that nitrogen is essentially pointless in commuter cars make a great deal of sense.