THIS IS NOT THE QUESTION YOU THINK IT IS.
(I know that it doesn’t expand as much when heated.)
I heard a Dunn Tire commercial that basically claims that nitrogen won’t leak from your tires.
They claim that low tire pressure causes poor mileage. OK, fine.
Soooooo nitrogen will never go low?
Correct if I’m wrong but, if your tire has an air leak then nitrgen would also leak.
WTF?
Can someone explain this to me or is this false advertising?
IIRC an oxygen molecule is 3 angstroms “square” whereas a nitrogen molecule is 4.3 angstroms by 3 angstroms, hence it’s not supposed to permeate through the rubber as fast as oxygen. In theory.
For a street car, filling the tires with nitrogen at a tire shop is horse shit IMHO. You’re starting with 78% nitrogen. Going up higher via grease monkey tire shop technique isn’t going to net you much of an increase.
HOWEVER
Any nitrogen production technique I know of will dry the living hell out of it (well south of -50*F dewpoints), which is good because a lot of the expansion from heating a tire is caused by the water vapor in the air in your tire.
All that being said, you will never see me pay to put nitrogen in my tires.
Although I am tempted to slap together a PSA nitrogen generator and offer nitrogen filling services at tracks days and autocrosses, where it actually could make a difference. Hmm…
If it’s good enough for the GTR, it’s good enough for me.
Here’s a powerpoint presentation from a Japanese company that supplied me with sieve for some nitrogen generators I designed and built specifically for tire filling. Check out the second slide for a visual of why they can claim that nitrogen won’t leak where oxygen will. (It’s bigger.)
http://www.kuraraychemical.com/Technical/CMS/CMS%20Presentation.ppt
Damn you awdrifter. Now you’ve got me considering quitting my job to travel the country running a track day nitrogen tire filling service for a living. :2fingers:
DO IT!
So if my leak is bigger than .43 nanometres air will work just the same?:biglaugh:
Edit: about 4 times already.
don’t you really need two valve stems so you can circulate to really get the most?
I think you may be missing the point, rubber is porous and smaller atoms/molecules will breath out slowly and larger ones will not. Has nothing to do with a leak, just the rubber itself.
^That’s still a leak, it’s just small.
Ah, purging. Yep, that would help a lot. Otherwise you can fill/empty a couple of times and/or pull a vaccuum on the tire before you fill it.
From what I have read so far I still say it’s a BS marketing scam.
I mean what, if you only check your tire pressure every 6 years you will find that nitrgen holds better?
BULLOCKS!
My tread is gone in about 6 months anyway and it is time to get new tires.
:wstupid:
We use nitrogen in the struts, and tires at the AFB. as for reasoning of why, i’m not entirely sure.
I do agree that it may help in performance situations since tire pressure becomes more critical.
Keeps the foam down in the struts.
(Oil foams less in nitrogen)
Cool, that I did not know. I know we rarely fill up our tires, so it must do pretty well.
Nitrogen is only useful on a track car - and only because it is drier than “normal” air - not because of any chemical crap. It just means its easier to keep tire pressures consistent regardless of ambient temp, humidity, blah blah blah
for anyone that didn’t catch the o.p.
Oh, I forgot. You’re a manager. Here you go:
Nitrogens are bigger than oxygens. Oxygens can squeeze through teeny tiny holes that nitrogens can’t fit through.
:tinfoilhat: <–Just for good measure. :tup: 
Nitrogen is BS. When I worked at west herr they charged like 17 or 19 bucks to “switch to nitrogen” 99% of the time we all used the regular air because it’s damn near the same thing.