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Was speaking with a colleag today and mentioned that she was low on one of her car tires, and that she should add some air. She then went on the explain that her tires were full of nitrous, not air. She pointed out that the valve caps were green, meaning they were nitrous.

I had never heard of this, and I thought it strange since nitrous can explode (and get you high).

Anybody ever heard of this? If so, can you add air to tires filled with nitrous?

Thanks!
 

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Powerhungry
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yeh nitrogen..its the NEW thing. doesnt go "stale" for lack of a better word. air will actually seep out of microscopic holes in rubber. the molecules of nitrogen are larger, thus preventing the sneaking out. and nitro pumps are damn expensive too. well so far..soon all service stations and shops will be running nitro instead of air
 

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Originally posted by nevada
yeh nitrogen..its the NEW thing. doesnt go "stale" for lack of a better word. air will actually seep out of microscopic holes in rubber. the molecules of nitrogen are larger, thus preventing the sneaking out. and nitro pumps are damn expensive too. well so far..soon all service stations and shops will be running nitro instead of air
That's what Nike uses in their Nike Airs!!
 

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Why are shocks filled with nitrogen? Is it for the same reason(larger molecules have a harder time seeping around seals)? I heard that it also prevents the oil in the shock from frothing. How does that work?
 

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neveda hit it on the spot from everything i have heard.. also one other thing i know is that nitro is not effected by heat or cold so 36psi is 36psi all the time..

use nitro lookin for leaks on HVAC systems for that reason
 

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Originally posted by jerzefigga
i think she meant nitrogen, not nitrous.
[:M86]

and last time i went in to Just Tires they offered it there and i dont remember it bein outragous
 

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Nitrogen has two properties that make it desirable for tire filling. First, as others have pointed out, nitrogen molocules are larger than oxygen and don't leak out of the tire as fast. Second, nitrogen doesn't expand as much as regular air does when it's heated, so tires pressures will remain closer to their cold pressure even as tire warms up. Nitrogen also won't support combustion, which is important when a tire takes a lot of abuse. Larger aircraft tires are filled with nitrogen - if they're not they can actually catch fire up inside the wheel wells after take-off. Airplanes have crashed when someone biffed and filled a tire with regular air.
 

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Antimatter knows what he's talking about. Nitrogen does expand as it is heated, but it expands at a lesser rate than the air we breathe. In contrast, CO2 expands at a greater rate than the air we breathe as it is heated(CO2 tanks are cheap/conveinent, but not ideal, i still use them in the desert though, sometimes). Does anyone know exactly why shock resevoirs are pressurized with nitrogen??
 

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yut uuuuugh!
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Oh boy, here we go... bring in the chem-geek

Ok, yes nitrogen molecules are "smaller" than oxygen molecules by roughly 2 picometers (1 pm = 0.000000000001 m), so we're not talking about a big/significant difference. Certainly not the scale that is shown on the above mentioned website (which interestingly enough is sponsored by a tire company). Where the difference lies however is that Nitrogen molecules are "lighter" than Oxygen by about 13%, which is a significant difference. What that means is that Nitrogen will move significantly faster than Oxygen, which will make it diffuse (read: leak) faster. So first off, Nitrogen tires will actually leak at a faster rate.

Next, the website states that regular air is 1/5 (20%) oxygen. Totally not true. "Air" is roughly 78% nitrogen, but the remaining stuff is composed of a mixture of oxygen, carbon dioxide, argon, helium, hydrogen, and a whole bunch of other stuff. My point? The remaining 20% is NOT oxygen. Oxygen will cause the tire to oxidize ("corrode"), which does make filling tires with pure nitrogen seem a good idea, so tires won't break down as fast. But think about it... the outside of the tire is still exposed to oxygen, and how many tires have you seen breakdown from the inside out?

Third, per unit volume nitrogen (28g/mol) is "heavier" than water (18g/mol). Since air has a high moisture content, for those of you who will say that getting rid of the water is good, you're replacing the water with something heavier. This creates more rotating mass, which makes you slower to accelerate, and harder to decelerate.

Fourth, if you want to talk about gas expansion, at the temperature and pressures we are dealing with the non-idealality of the gases is negligible. In other words, since we are dealing with relatively low pressures and temps, the amounts of expansion per unit volume between nitrogen and "air" will be pretty much the same. You would see a big difference if we were near the melting/freezing point of one of the substances and not the other. That is not the case here. Nitrogen is at -210 C, and Oxygen is at -218 C.

Finally, the pump that you use to put "air" in your tire pumps in about 80% nitrogen (free). You're paying a crap load of money for that extra 20%, which I’m willing to bet you will not see a 20% increase in efficiency. Is it really worth the money? Are you really going to "tell" the difference? You may think it's "better for the environment", but have you thought about what has to be done in order to liquefy the nitrogen in the first place? I'm not saying it's bad, but most people hear about a new environmentally conscious procedure and sign up whole-heartedly before looking into the steps that lead up to the procedure to see if they are also "better".

Oh yeah, and in case you think I'm spitting random crap (I have said this before but) I do know what I'm talking about here. I have a degree in chemistry, teach chemistry, and right now I'm working in a research lab at the University of Rochester in New York along with 3 chemistry PhD's, 2 chemistry masters degrees, and 1 chemistry post-doc. And we have been talking about this one for a while... mainly laughing at the people who think this actually works.

Ok, I'm done now... feel free to flame if you feel the need, but I'm just trying to shed some valid light on this subject.
 

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Nitrous is not explosive like you think it is though.. You're seen The Fast & The Furious one too many times. "NAWWWWWWWWWZZZZZZ!" ;)
 

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wow if thats true it goes against everything thats been published so far. not that im saying i believe everything i read, including this. and i do know that we use nitrogen in our pb guns. it much cleaner and works better....
 

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yut uuuuugh!
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when you fill up your canisters (not using nitrogen), do you fill them up from a compressor or from a compressed air cylinder? If a compressor is used how far from the pump are you? I ask because compressors have a nack of throwing a little bit of oil out a short distance, so in that case a nitrogen tank would be awesome. It's all positive pressure. As the liquid nitrogen evaporates the gas pushes itself out.

For the sake of general knowledge, where is the stuff that's published. I'd be interested to read it... perhaps there is something I haven't thought of. I mean sitting in a group of really smart chemistry people, you would think that something would come up if it was plausible. But then again, new inventions/methods that come up are created when people try to make stuff work outside the box. So yeah, if you know where I can find some stuff on that I'd like to check it out. I'll do some research of my own too. Thanks!

~ rick
 

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Nitrogen is used in shocks because it is an inert gas meaning it doesn't assist in degrading the seals or rusting the metal, and the larger molecule of nitrogen also makes it less susceptible to leaking. Also nitrogen gas has good compression qualities for shock applications.
 

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Huh, I stand corrected on the first two points of my post. I guess the car racing dudes just like to spend money on their doo-dads.

I'm pretty sure I'm right on the last point, though. I was just reading that large aircraft tires are inflated to 200 PSI, and I know that the landing speed for some aircraft can be in excess of 100 knots. The Boeing 747 lands at 124 mph, with full flaps and gear down. You figure that several tons of aircraft smacking into the runway at 120+ mph has got to put a lot of stress on a tire.

If you're curious about what happens to someone who overfills a large aircraft tire, look at the bottom of this page in Table 1.

http://www.boeing.com/commercial/aeromagazine/aero_05/textonly/m03txt.html
 

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Originally posted by antimatter
The Boeing 747...You figure that several tons of aircraft smacking into the runway
Talk about an understatement. :D

I think the Airbus 380 has a maximum take-off weight of somewhere around 230 tonnes, which is simply ridiculous. Of course, it can't really land at that weight, but it would still probably weigh over 150 tonnes upon landing.
 
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