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Nitrogen in tyres


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Hi Guys


Saw a similar post but didnt get clarification.


My local Total service station has N2 available.

Ive used it in my cars for years and can vouch that the pressures stay contstant for longer than normal air.


Will this hold true for bike tyres or are these just too "porous" for even N2

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You don't wanna do that coz its heavier than air.


and I thought the molecular mass of N2 is slightly lower than that of air... <_< 28.02 vs 28.97 kg/kMol respectively...

The O2 molecules are smaller, so migration thru rubber of nitrogen is less. But I dont think there is that of an advantage as the biggest advantage for using N2 over air was the reduced variation in pressure as tire temp changed. what's the tire temp change of road and MTBs during a typical event?

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You can only use the N2 where it is not a freeway.

It was nearly too early for me to get this, luckily I had my 1st cup of coffee :D

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Nitrogen gas is used in Tour de France bike tyres.


The key benefits are a slower rate of pressure loss and cooler running temperature of tyres.

The molecular structure of nitrogen differs from that of air, in such a way that it escapes through the tyre’s inner liner or tube at a slower rate than regular compressed air.

The result is a dramatically slower rate of pressure loss in a tyre filled with nitrogen. For example, it might take up to six months to lose 0.14kpa with nitrogen, compared to just one month with compressed air.

As tyres heat up, their inflation pressure increases, which then reduces the size of the tyre’s footprint the tyre then loses grip because of this smaller footprint. So the cooler they run the better the tyres will grip the road.

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I read an interesting article that said that because O2 was the first thing to escape all the time, you eventually have nearly only N2 in your tires anyway if you keep on topping them up. This is barring punctures of course.

Also by only running nitrogen there is less intermolecular friction and thus the tires will stay cooler easier and then the pressure won't change as much as @Paulst12 said.

Personally I think the whole thing is a load of rubbish but it you're at the top of your game and you're looking for more things to do then sure, go for it.

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Don't make your riding more complicated than it needs to be. Unless the surface temp of your tyres is getting to 80 or 90deg you're wasting your time. Even then the "contact patch" area on a bike's tyre from cold to hot would not change that much. That's my 2 bits.

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