Nitrogen in Bike Tyres?

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MikeAqua

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#195058 4-Apr-2016 15:29

Has anyone tried nitrogen in bike tyres?

I'm not sure how it would be accomplished but I get sick of having to top up bike tyres frequently.

I've certainly noticed a significant difference switching from air to nitrogen in vehicles.

Mike

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#1525837 4-Apr-2016 15:44

Air is already almost 80% Nitrogen...

timbosan

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#1525847 4-Apr-2016 15:53

freitasm:

Air is already almost 80% Nitrogen...

This is what I don't get - why pay $5 per tire to have something put in there that is already free?

networkn

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#1525849 4-Apr-2016 16:03

If you want to move faster, fill with Helium! :)

Jase2985

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#1525852 4-Apr-2016 16:07

i take it you are talking Motorbike tyres not push bike

"Air-filled tires, originally filled to 30 psi lost 3.5 psi over a one year period.
Nitrogen-filled to the same starting pressure of 30 psi lost 2.2 psi over the same period."

To be honest not worth the hassle or money

Dratsab

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#1525854 4-Apr-2016 16:09

freitasm: Air is already almost 80% Nitrogen...

This is what I was going to say. On top of this, if you're "constantly" having to top up your tyres you possibly either have a faulty valve or a very small hole in the inner tube/s somewhere. Due to the thin, soft nature of bike tyres it's a good habit to get into (imho) to deflate them every week and give them a thorough inspection for bits of glass.

EDIT: Good point Jase2985 - I'd automatically assumed pushbike due to their being no "motor" in front...

Oblivian

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#1525865 4-Apr-2016 16:30

I had to wonder last tyre service.. visually followed the cable from the nitrogen tank, and note it also passes through what appeared to be a standard O2 tank..

The biggest thing with it from what I could tell was less expansion from heat

BlueShift

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#1525868 4-Apr-2016 16:41

Jase2985:

i take it you are talking Motorbike tyres not push bike

"Air-filled tires, originally filled to 30 psi lost 3.5 psi over a one year period.
Nitrogen-filled to the same starting pressure of 30 psi lost 2.2 psi over the same period."

To be honest not worth the hassle or money

Presumably, since N filled tyres lose pressure more slowly, the air filled tyres are losing the oxygen and carbon dioxide portion faster than the nitrogen. Hence, after a few top ups, they'll be mostly nitrogen anyway.

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Journeyman

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#1525870 4-Apr-2016 16:48

Oblivian:

The biggest thing with it from what I could tell was less expansion from heat

Precisely. You do't need nitrogen in your car tyres unless you're a race car driver.

Jase2985

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#1525875 4-Apr-2016 16:54

"Conclusion of Low Pressure Gas Test:
Through a 128ºF temperature swing from -11ºF to 117ºF all gas samples showed virtually an identical pressure increase of 17 PSI from 40 PSI to 57 PSI. For an automotive tire this temperature delta represents an extreme real-life case but it shows that the Ideal Gas Law formula does apply to these gases and when it comes to thermal pressure stability none has any apparent advantage over the other."

Jase2985

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#1525886 4-Apr-2016 16:56

The only real difference i can see is nitrogen is "Dry" and regular air is "moist", ie has some moisture content. this probably pays a part in thermal stability but on the street its likely to make zero noticeable difference.

if you have the money go for it

Athlonite

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#1525917 4-Apr-2016 17:37

the only thing I found using Nitrogen in my car was the tyres were a little quieter on the road and lasted a little longer before I needed to replace them (+15000K's) so for me it was worth it

frankv

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#1525926 4-Apr-2016 17:57

Oxygen molecules are smaller than Nitrogen ones, so they leak through the rubber. So, you start with air. Once the pressure is down to 80%, you're on pure Nitrogen. Top up with air, and you've got 4% oxygen, 96% nitrogen. After another top-up, it's 0.8%

blackjack17

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#1525935 4-Apr-2016 18:12

frankv:

Oxygen molecules are smaller than Nitrogen ones, so they leak through the rubber. So, you start with air. Once the pressure is down to 80%, you're on pure Nitrogen. Top up with air, and you've got 4% oxygen, 96% nitrogen. After another top-up, it's 0.8%

I don't know if this is right based on general science principles.

First off you are assuming no losing of Nitrogen

Secondly as the difference in proportions in air within and outside the tire become greater the concentration gradient becomes greater which means it is easier for nitrogen to defuse out of the tire.

The above is based on the idea that nitrogen can diffuse across the tire rubber

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JWR

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#1525990 4-Apr-2016 19:54

Isn't using Nitrogen mainly about eliminating water vapour and reducing fire risk?

Water changes from solid, liquid to gas in a narrow and commonly experienced temperature range.

That will mess up pressures in extreme applications like commercial aircraft or Formula 1 tyres.

Compressors tend to build up water, in the expansion tank. That's why the tanks usually have a drain plug.

If you want accurate and consistent pressure then fill it from known, pure gas storage tank.

Gases expand by the same rate with temperature - see Charle's Law. So after eliminating the water vapour, then any gas would behave the same.

But, obviously using something like Oxygen or Hydrogen is a huge fire/explosion risk. Both, in storage and filling

So something relatively inert and cheap like Nitrogen, is used.

There other reasons given. But, I think they are BS.

If you aren't running an airline or racing then I wouldn't consider using Nitrogen in tyres.

freitasm

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#1525992 4-Apr-2016 19:57

If the OP is pushing his bike at aeroplane or F1 speeds then I'd worry about other stuff first.

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