Nitrogen filled M/C tyres?

[Badjelly]

So let's put an end to this non-sense that nitrogen is more dense than air and oxygen. It isn't. What I do not know, can not easily find and can't be arse calculating is the molecular cross-section of the two molecules, this matters when considering diffusion through permeable media.

Did anyone say that nitrogen is denser than oxygen? I didn't notice. What someone did say is that it diffuses more slowly. As you say, this is a function of the molecular cross-section. Wikipedia notes that

Nitrogen molecules are less likely to escape from the inside of a tire compared with the traditional air mixture used. Air consists mostly of nitrogen and oxygen. Nitrogen molecules have a larger effective diameter than oxygen molecules and therefore diffuse through porous substances more slowly.

and cites this paper:

http://dx.doi.org/10.1063%2F1.1707667

So there you go. No need for any more discussion of this topic!

[The Stranger:Me]

I did - and combined with the results of the Clemson Uni Study quoted above I'd say you're right - it could leak through the bead or the valve - and it would probably happen about 70% faster with air than Nitrogen.

Thanks for the invitation to think about it... turns out you're wrong on a number of counts. C'est la vie.

Open invite to find a reputable source that says I'm wrong. Prefer peer reviewed/scientific type resources if that's ok. KBers are prone to saying things without actually thinking... or knowing. What're the chances?

My daughter used to get pissed at me for always "winning" our arguments.
The way I would "win" them is to not argue about shit I know nothing about, quite simple really. I would have thought it obvious, but apparently not.

[Mikkel]

Does too...

Does not...

Agreed, but ... argh can't be fagged... here - read this (pdf warning)

Yep, that was kinda what I was getting at. One thing I do dislike about the pdf-file is that he just says "it actually is" without providing any references.

We used to calculate the length of molecular bonds back during my undergrad years - and the size of molecules very much depends upon this and how tightly bound the electrons of each individual atom are. But, I have forgotten almost all of the details of this by now and I can only recall it was frightfully tedious and that I am glad I don't have to do it for a living.

[Mikkel]

Did anyone say that nitrogen is denser than oxygen? I didn't notice. What someone did say is that it diffuses more slowly. As you say, this is a function of the molecular cross-section. Wikipedia notes that


and cites this paper:

http://dx.doi.org/10.1063%2F1.1707667

So there you go. No need for any more discussion of this topic!

Does not...


In actual fact, if you keep on filling your tyres with air they will eventually siphon all of that nasty oxygen out of your tyre and you'll be left with nitrogen-enriched air in your tyres for free. Coole eh!

[UberRhys]

Yes, using a purified and completely dry gas could make a difference in regards to consistency - something which is very important in all scientific pursuits (e.g. F1). Also, I can not imagine any downsides to putting pute nitrogen (not liquid mind) in tyres compared to normal air.

Now there is a thought... liquid nitrogen filled tyres - choice one... We freeze stuff at work with it all the time. THEN WE SMASH IT for fun of course...

In actual fact, if you keep on filling your tyres with air they will eventually siphon all of that nasty oxygen out of your tyre and you'll be left with nitrogen-enriched air in your tyres for free. Coole eh!

A very long way to get Nitrogen into tyres, but you will still have the issue of moisture which will expand under heat and allow the pressure to fluctuate.

[varminter]

So.... fill your tires with helium and float over the opposition.
Fill with plutonium and everyone will avoid you
Fill with nuetronium and ride straight to the center of the earth

[thepom]

Aircraft use nitrogen in their tires as it is an inert gas and lowers the risk of fires started by hot brakes and the wheels blowing,maybe the same for F1 but hey who is stupid enough to pay for it in their car or bike? not me for one!

[reofix]

Nitrogen filled tyres are bollocks, except that the air might be drier, so less prone to expansion and contraction. Air is 80% nitrogen anyway.
Try googling "nitrogen filled tires" and read some of the studies.

[Dak]

Nitrogen filled tyres are bollocks, except that the air might be drier, so less prone to expansion and contraction. Air is 80% nitrogen anyway.
Try googling "nitrogen filled tires" and read some of the studies.

Exactly, I work at a place that sells the stuff and I agree, for joe average it is BOLLOCKS!

[Devil]

Try googling "nitrogen filled tires" and read some of the studies.

Try googling Nitrogen Tyre research instead and get the actual studies instead of peoples opinions and retarded conclusions.

[Devil]

Exactly, I work at a place that sells the stuff and I agree, for joe average it is BOLLOCKS!

Oh god. seriously. Dont breed.

Because it has little to no discernable effect for joe bloggs, doesn't mean that it doesn't work for others, ie commercial vehicles, for which it is mainly pushed.

Little to no effect on subject X doesn't mean that it doesn't work ever.

Too much opinion and poor conclusions, too little fact.

[2_SL0]

Cant be farked posting an answer. Could use Nitrogen, Dry Air, etc, its the moisture content that is the issue.
Cost wise, Nitrogen is one of the cheapest.
I know of a number of commercial trucking companies that use it in Europe.

[ManDownUnder]

This is a great thread.
Re Nitrogen
Benefit 1) Nitrogen filled tires don't lose pressure so fast because N2 is physically bigger than O2, a consituent of air. Both N2 and O2 and escape through tire walls but N2 does it a lot more slowly
Expense 1) It's costs money to put in there, and more money every time you pump your tires up (What's the point of exluding oxygen at the initial fill then chuck in it as part of the air used to top tires up?)

Re moisture (entirely different topic in my mind
Dry Air or Nitrogen will exclude moisture which expands at temperature therefore tire pressure will be more stable with dry gas then not dried gas.

There's a shitload of posts saying I think this and I think that with fuck all backing them up. Try a little academic research... the Internet is your friend. Look up actual studies, cite some reasearch and it's give you a good argument and (as I have) actually learn something along the way.

Seriously - don't take my advice on this stuff. Google it. Include the words "research" "university" and "study" in the search string, then read the factual results of actual work done to establish the facts.

You might happen to like Bob, but that doesn't make everything he says true.

[98tls]

Why anyone would pay for something when they can achieve the same result for zip is beyond me,then again its Kiwis we are talking about.Possibly a fashion thing? Something to talk about over a latte in Auckland "look at my tires there simply bulging with Nitrogen"No doubt the school run in the obnoxious never been never will be off-road 4wd will be the much safer with Nitrogen filled hoops.Load of bollocks.

[3umph]

I'm amazed the banter is still going on about this...

The main thing is no major benefit of running it for the general public in bikes is the common thing I have read....