Another pub discussion topic for the Physicists.

[MIG Wielder]

You have probably heard about tyre companies offering to inflate your tyres with dry nitrogen gas for a fee ?
http://www.theaa.com/motoring_advice/sa ... rogen.html
The advantages being no corrosion and reduced rate of diffusion.
Well, there are other gasses around. Like carbon dioxide which we think has a much larger molecular size and rate of diffusion is even less. It is also a good conductor of heat to keep the tyre cooler for road use.
Is there any reason that Carbon Dioxide is not used to inflate tyres ?
Tony.

[Karlos]

I was thinking that maybe nitrogen is cheaper -because there is so much more of it - 78% of air is nitrogen. Then I thought it can't be a cost issue as fizzy drinks use CO2, I wonder why they can't use nitrogen in drinks?
In F1 I am sure they have possibly tested and tried a variety of gases in the tyres, but I think the regs state air or nitrogen only.

[Carledo]

I was thinking that maybe nitrogen is cheaper -because there is so much more of it - 78% of air is nitrogen. Then I thought it can't be a cost issue as fizzy drinks use CO2, I wonder why they can't use nitrogen in drinks?
In F1 I am sure they have possibly tested and tried a variety of gases in the tyres, but I think the regs state air or nitrogen only.

Would nitrogen in fizzy drinks give you the bends?

Steve

[Galileo]

CO2 is quite soluble when it comes to butyl rubber, so you would get more leakage than with plain old air. As to temperature, at normal tyre temperatures most gases individually behave the same, though because air also contains water vapour the pressure would remain more constant when using any gas on its own.

My vote's for helium filled tyres!

[Karlos]

Now I learned that helium is a very small molecule that can squeeze its way out of a tyre. If you have ever had helium balloons for a party never get them the day before. when you first inflate them they are floating against the ceiling, next morning they are 1/2 inflated and on the floor as the gas has escaped.

Hydrogen filled tyres on magnesium wheels could get interesting

[Carledo]

Hydrogen filled tyres on magnesium wheels could get interesting

Well they'd certainly make you more careful about kerbing them!

Steve