Nitrogen filled M/C tyres?

[ManDownUnder]

Tyres are impermeable. There is zero diffusion through the rubber.

The only way that the gas inside a tyre can escape is either:

a. Through the valve (or stem).
b. Through the bead.

Using Nitrogen to fill your tyres has no effect on either of these.

Think about it.

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?

[Squid69]

*yawn*... read this
and this

...of note to me...
Due to nitrogen's larger molecular size, it migrates through a tire three to four times slower than oxygen. Whether a truck tire is parked on a trailer or running down the road, if it's filled with "plain old air" it will lose approximately 1.4 to 1.7 psi every week.

According to a 2007 Clemson University study, nitrogen reduces this loss by 69 percent or greater.

They're talking about truck tires. A shit load thicker/stronger and I would expect harder for gases to escape from. As sixpack alluded to - fill the bastards with Helium and watch the fun.

NEXT!

They also have shitloads more surface area than bike tyres... I would assume that gaps between the rubber molecules are still the same size, no matter what hardness the tread compound is.
You will probably also find that aside from having more rubber, and compeltely different reinforcing, truck tyres and motorcycle tyres are not that much different in construction

I was under the impression that nitrogen was used because when it heats up it does not expand as much, therefore making it easier to keep the tyres at a constant pressure...

[ManDownUnder]

They also have shitloads more surface area than bike tyres...

I was under the impression that nitrogen was used because when it heats up it does not expand as much, therefore making it easier to keep the tyres at a constant pressure...

Quite right but volume of a tyre increases at the same rate as surface area so that can be discounted.

[UberRhys]

I was under the impression that nitrogen was used because when it heats up it does not expand as much, therefore making it easier to keep the tyres at a constant pressure...

Dry nitrogen is just that - dry nitrogen, ie: Nitrogen with no moisture in it.

Compressed air from an air compressor like that in workshops or at service stations is air made up of (mainly) Nitrogen (78.084%), Oxygen (20.947%), Argon (0.934%), Carbon Dioxide (0.033%) which makes up 99.998%. The balance is made up of other traces (Neon, Helium, Krypton, Sulfur dioxide, Methane, Hydrogen, Nitrous Oxide, Xenon, Ozone, Nitrogen dioxide, Iodine, Carbon monoxide, Ammonia).

In addition to the mixture that is air, moisture gets worked into the mix, espically when compressed - and this is what causes the fluctuations in pressure. As the tyres warm up, the moisture content heats up and expands causing the fluctuations in tyre pressure. no matter how good of an inline drier you have on the compressor, moisture always manages to find it's way there.

[roogazza]

Perhaps the backyard scientists among us could actually go look up the facts directly related to nitrogen use, from reputable sources, instead of pretending they know everything, or quoting other backyard scientists.

It's been proven, it works. I dont know why this discussion has come up again.

I've used it when running a Z1 in Six Hour races. The idea was to keep the tyres cooler, whether it worked , don't know for sure ?
I believe the powers that be banned using it after a two years.

But if the modern generation says hoggwash ? LOL Gaz.

[Renegade]

Dry nitrogen is just that - dry nitrogen, ie: Nitrogen with no moisture in it.

Compressed air from an air compressor like that in workshops or at service stations is air made up of (mainly) Nitrogen (78.084%), Oxygen (20.947%), Argon (0.934%), Carbon Dioxide (0.033%) which makes up 99.998%. The balance is made up of other traces (Neon, Helium, Krypton, Sulfur dioxide, Methane, Hydrogen, Nitrous Oxide, Xenon, Ozone, Nitrogen dioxide, Iodine, Carbon monoxide, Ammonia).

In addition to the mixture that is air, moisture gets worked into the mix, espically when compressed - and this is what causes the fluctuations in pressure. As the tyres warm up, the moisture content heats up and expands causing the fluctuations in tyre pressure. no matter how good of an inline drier you have on the compressor, moisture always manages to find it's way there.

everyone go down to their local powder coaters, the inline compressed air dryers are top notch, basically cant have moisture in the lines if your blowing fine powder, fill ya tyres up there for free.

[vgcspares]

hmmmm - Helium you say ?

Wouldn't that reduce the sprung (as opposed to the unsprung) mass - which would give improved suspension at the cost of needing daily top-ups due to the smaller molecules escaping faster ..... or would you need to fit truck tires ?

[ManDownUnder]

hmmmm - Helium you say ?

Wouldn't that reduce the sprung (as opposed to the unsprung) mass - which would give improved suspension at the cost of needing daily top-ups due to the smaller molecules escaping faster ..... or would you need to fit truck tires ?

LOL that's be quite an expense mate... for fuck all weight saving

[elevenhundred]

There seems to be a lot of armchair scientists in this thread.
In reality most of them's experience with gas is with the stuff that comes out their bum, and that stuff is by no means noble or inert

[3umph]

the big question is... for Joe public like me is there any advantage/dis advantage to using the nitrogen or world we not notice any difference??

my guess is that no difference would be noted by joe public

[Mikkel]

It does so...

Does not...

Fill a tyre with Helium and see how impermeable rubber is......only have to look at Helium filled balloons to see how well it contains light gas [yes some helium will leek out of the seal, but if you did a back-to-back test with air filled balloons the result speaks for itself.............rubber is permeable [but contains Nitrogen pretty well]].

Looking at Nitrogen, Oxygen and air:

Nitrogen:
Density - 1.165 kg/m^3
Atomic weight - 14.0067 U

Oxygen:
Density - 1.331 kg/m^3
Atomic weight - 15.9994 U

Air(78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide):
Density - 1.205 kg/m^3

References:
http://www.engineeringtoolbox.com/ga...ity-d_158.html
http://www.webelements.com/


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.

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. Worth $5 a tyre? I don't think so...

Any of the "non-believers".

I think this strikes closer to the heart of the matter. For everyday motoring the belief-factor of having nitrogen filled tyres is probably a few orders of magnitude more influential than the physical side of things.

[Badjelly]

the big question is... for Joe public like me is there any advantage/dis advantage to using the nitrogen or world we not notice any difference??

my guess is that no difference would be noted by joe public

Well, given that Joe Public isn't very observant, this a bit of a loaded question, but...

I think the only difference you might notice is that your tyres wouldn't lose pressure quite so quickly.

[Devil]

the big question is... for Joe public like me is there any advantage/dis advantage to using the nitrogen or world we not notice any difference??

my guess is that no difference would be noted by joe public

For Joe Public (bike rider in particular). You probably wouldn't notice a difference.
For high mileage vehicle, commercial driver, you're most likely to see the benefits.

I dont use it, I dont have a need for it.

[Sully60]

My, this is quite the disscussion considering it's about inert gas.

Imagine how it would go if we used Ununoctium somewhere in our motorcycles

[ManDownUnder]

Does not...

Does too...

Looking at Nitrogen, Oxygen and air:

Nitrogen:
Density - 1.165 kg/m^3
Atomic weight - 14.0067 U

Oxygen:
Density - 1.331 kg/m^3
Atomic weight - 15.9994 U

Air(78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide):
Density - 1.205 kg/m^3

References:
http://www.engineeringtoolbox.com/ga...ity-d_158.html
http://www.webelements.com/


So let's put an end to this non-sense that nitrogen is more dense than air and oxygen. It isn't.

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

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.

WOAAAAA there... you're not claiming to know it all - you don't fit in around here at KB do ya man??? LOL (p/t)

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. Worth $5 a tyre? I don't think so...

I think this strikes closer to the heart of the matter. For everyday motoring the belief-factor of having nitrogen filled tyres is probably a few orders of magnitude more influential than the physical side of things.

LOL - total agreement there. The theory being one thing - the practical reality is something compleeeeeetly else.