are you "N"?

[MitsuMan]

so at my shop we just started filling tires for 3.50 a piece with nitrogen. It keeps the tires cooler than air. Really it works, it also is denser than air so it stays at the pressure you set it to longer. The air has more h2o in it which promotes wheel rust and also oxidation on aluminum alloys. Plus the air penetrates the actual rubber faster than the nitrogen because of the density. and the rubber deteriorates faster as a result
Just thought you moders out there that have nothing left to buy might want some F1 inspired high performance tire inflation info

what do you guys think??? :? 8)

[ace33joe]

I am interested. Where is your shop? :)

[Evo442]

Hey, thats pretty cool. Finally someone besides Costco is filling tires with nitrogen.

Out of curiosity, what starting pressures would you recommend for RA-1s at the track? How much variation in pressure would I expect to see once the tires are warmed up?

[Unowned]

Air at sea level is 78% Nitrogen... not sure that helps much...

http://www.physlink.com/Reference/AirComposition.cfm

[EvolvedDSM]

Air at sea level is 78% Nitrogen... not sure that helps much...

http://www.physlink.com/Reference/AirComposition.cfm

Pretty much what I was thinking...

Molecular mass of Nitrogen is 28.02 vs. 28.97 of air (roughly 3%).

[Whooopasss]

dont you need a special valve stem for this?

[Unowned]

Now if you can fill those tires with Helium, that would grant noticable gains...

[EvolvedDSM]

Here's something else... How does the smaller Nitrogen molecule stay in the tire better? Granted there are other trace elements in air, but Nitrogen, Oxygen, Carbon Dioxide and Argon account for 99.998% of air and these are all equal to or larger than the Nitrogen. Even the majority of the other components are larger.

[EvolvedDSM]

http://www.eng-tips.com/viewthread.cfm?qid=120996&page=1

The most memorable quote from the thread:
The bottom line is that for general passenger car tires or truck tires there is nothing to be gained (other than portability) by using nitrogen rather than air. The biggest gain will be $$$ by the companies that sell nitrogen handling equipment and the tire merchants that appeal to ignorant customers. And who is the biggest loser? Yep, the consumer.

[EvolvedDSM]

Now if you can fill those tires with Helium, that would grant noticable gains...

http://www.newton.dep.anl.gov/askasci/eng99/eng99085.htm


Second, helium diffuses very rapidly through rubbery materials -- the cause
of the short life of helium filled latex party balloons. Aluminized Mylar is
much better. But this could be a problem if tires kept "going flat".

Third, helium diffuses readily into some metals. This could be important, if
it causes embrittlment.

[vtluu]

Nitrogen has been discussed before here: http://www.norcalevo.net/forums/viewtopic.php?t=1966

To repeat ez76's quote:


Inflating tires with nitrogen offers a host of benefits. It contains no moisture so rims won't corrode. Nitrogen doesn't leak away like compressed air, which can cause a 1.5-psi drop per month. Nor does nitrogen react with rubber the way oxygen in compressed air does. This oxidizing reaction can cause premature tire wear and blowouts. And nitrogen prevents hot, flammable gases from building up inside tires. It also brings up to a 25% increase in tire life to the bottom line.
To which I would say: with my aluminium alloy rims corrosion isn't really an issue, I'm not exactly worried about a "1.5-psi drop per month" given how often I check and set my tire pressure, nor is oxygen reacting with rubber and consequent tire life a factor when I go through 4-6 sets of tires a year. So, it's definitely not for me, especially when it would mean that I'd have to haul around a tank of nitrogen to the racetrack. I barely have enough room for tires, tools, luggage and supplies as it is! 8)

[Unowned]

Well i'm not saying Helium can be used with current tire technology. It would find it's way out of the holes in the rubber. On the Rim and inside the tire would need to have some sort of inner coating material to prevent Helium from escaping.

[vtluu]

Well i'm not saying Helium can be used with current tire technology. It would find it's way out of the holes in the rubber. On the Rim and inside the tire would need to have some sort of inner coating material to prevent Helium from escaping.
All right, time to dust off my high school chemistry; let's compare Helium (an inert gas so it's always in single-atom molecular form, He) and Nitrogen (N2). Both gases follow the Ideal Gas Law, PV = nRT. For simplicity's sake let's have P = 2 atm (29.4 psi, a pretty reasonable race tire pressure), T = 300 K (80 F, "cold" tire), V = 14 litres, R = 0.0821 (constant for units Moles, litres, atm and K).

So we have n = PV/RT; note the molecular weight of the gases don't enter into this equation (it's called the "ideal" gas law partly for this reason but it's very much good enough for our purposes). Solving, we get n = 2 * 14 / (0.0821 * 300) = 1.14 Moles (about 6.85 * 10^23 molecules, if you will).

The molecular weight of He = 4.003, so 1.14 Moles of it weighs 1.14 * 4.003 = 4.56 grams (0.010 lbs).

The molecular weight of N2 is 28.0134, so 1.14 Moles of it weighs 1.14 * 28.0134 = 31.9 grams (0.070 lbs).

So you net weight savings--per tire--would be about 26.8 grams, or 0.059 lbs. And that's not counting the weight mylar film (etc.) you would need to keep the He from diffusing out of the tire.

Still think it's worth it? ;)

[vtluu]

The shorter answer is that if Helium were truly beneficial, F1 teams with millions of dollars of R&D money would have found a way to use it.

[zyounker]

From my understanding the reason nitrogen is nice in tires is because you have much more stable tire pressures when running. Very few people here would make it hard to refill tires as most places do not offer it.


Still cool IMO. (Options are never bad)

[ace33joe]

I am interested. Where is your shop? :)

I don't care whether it is worth or not, I just want to try them. So where is your shop located, MitsuMan?

[BMan]

Now if you can fill those tires with Helium, that would grant noticable gains...

My uncle did that to lower the weight of his car to get into Jr. Dragster class at Lyon's drag strip in the '60's. The problem is that the atoms are really small and escape through the rubber very quickly.

[chrisw]

The shorter answer is that if Helium were truly beneficial, F1 teams with millions of dollars of R&D money would have found a way to use it.

no way man.... Hydrogen... only way to go.. Few minor glitches to work out :shock: , but if you can save 0.059lbs with helium, imagine the weight savings using hydrogen instead....

:lol:

you certainly would not have to worry about the hydrogen attacking the tires, well, only until the tires get some heat in them. Then you would have no tires to worry about.