One for the tyre experts....

[scarbs]

It's not that I doubt your first-hand sources Scarbs, but why than all the websites dealing with this problematic mention that F1 teams use nitrogen or mixture of nitrogen and some other gases (including some very fresh articles)?

Because I asked the tyre companies recently and got that as the response. Bridgestone even had this in their press release a couple of years ago. The transport of the gas cylinders was the major issue and as its the water content in normal undried air that causes the heat related pressure changes, the dried air supply negates any advantage of bottled Nitrogen.
Hydrogen in tyres! Are you crazy? Have you seen the spark and heat expelled durign a blow out of a collision with a barrier, having the tyre fuel of flammable gas would cause either a small explosion or at least flash fire. As for weight savings...!

[Mikey_s]

Thanks to all for the responses.

It looks as if there is no concensus on the response, other than the fact that most of the arguments supposedly supporting significant differences don't stand up to scrutiny.

Scarbs,

there has been another thread on Hydorgen in the engine section - agree with your comments about safety - but then again perhaps Helium could be used..? just a thought! Nevertheless - I think that repainting gas cylinders is probably illegal for safety reasons and F1 is always very strict about safety.

My thoughs on some of the other responses;

I don't accept the arguments about reactivity of O2 leading to tyre damage - certainly this would be just as much an issue to the outside of the tyre carcass, and UV would be a much greater threat to this ageing mechanism - plus, for the 2h of a race I think the tyre should be able to with stand O2 attack.

It is possible that the specific gravity could be ther reason, but frankly in practivcal terms I think the difference would be unmeasurable.

My sense is that they use bottled N2 because it is a) dry and b) less bulky than carrying round a compressor.

Thanks again for your input, it's been an interesting thread.

[manchild]

...Hydrogen in tyres! Are you crazy? Have you seen the spark and heat expelled durign a blow out of a collision with a barrier, having the tyre fuel of flammable gas would cause either a small explosion or at least flash fire. As for weight savings...!

I wrote nitrogen, the Guest wrote hydrogen.

[Apex]

So when all has been said and done, you were correct Mickey_s

[Guest]

I am not crazy, just quoted out of context. Yes I suggested hydrogen had advantages but I also added if flamability was a concern helium was the next best choice.

[DaveKillens]

F1 teams travel all around the world, so logistics (and time mangement) is very important. They could carry around two (gotta have a spare in case of failure) air compressors with filters and such to eliminate the water and other impurites. Or they could just rent/buy nitrogen cylinders. In most places, quality can be assured. It's a lot simpler to just pack along the regulators, hoses, air guns, than to carry along additional compressors that most likely will require attention during the race weekend.
Hydrogen is the smallest molecule, so there is no known material able to completely contain this gas. It will leak out over time. But it is a slow leak. And the gas inside the tyre accounts for a very small fraction of the unsprung mass. And the difference in total unsprung mass between ordinary air or hydrogen of helium is negligible.

[manchild]

Wow! This is another thing formula1.com lacks - "chemical analysis"