Nitrogen in tyres.

[kaanage]

Oxygen and nitrogen? Water is made of two hydrogen atoms and one oxygen atom and heating water does not cause it to split up. Think about it, when you boil a kettle of water, the vapour that comes out as steam is water vapour, not hydrogen or oxygen as individual elements. Water will only split into hydrogen and oxygen through special processes. Heat will not do it.

Yes, the benefit of removing the water vapour is that the vapour pressure rises exponentially with temperature, rather than linearly from a base of ~ -273 deg C as ideal gasses behave (which nitrogen and most of the other gasses composing "air" approximate well at the temperatures that car tyres face). This is why the tyre pressures are so much more temperature stable with nitrogen fill.

[alexaescht]

Yes, the benefit of removing the water vapour is that the vapour pressure rises exponentially with temperature, rather than linearly from a base of ~ -273 deg C as ideal gasses behave (which nitrogen and most of the other gasses composing "air" approximate well at the temperatures that car tyres face). This is why the tyre pressures are so much more temperature stable with nitrogen fill.

I understand that. I was pointing out that Sydneykid's analysis of making the tyre hot to allow the water to 'split into nitrogen and oxygen' is totally incorrect. That doesn't happen.

[wai]

Of course, one of the reasons it is used in aircraft (and racing) is that the last thing you want in an accident that results in a fire is a pressurised source of air with oxygen to help fuel any fire.

Nitrogen is also used in racing to operate the rattle guns. Again, you do not want high pressure air available where you are handling fuel.

For road use, there is no benefit.

[kaanage]

I understand that. I was pointing out that Sydneykid's analysis of making the tyre hot to allow the water to 'split into nitrogen and oxygen' is totally incorrect. That doesn't happen.

Of course. I was also commenting for Sydneykid

[Hail22]

[Sydneykid]

I understand that. I was pointing out that Sydneykid's analysis of making the tyre hot to allow the water to 'split into nitrogen and oxygen' is totally incorrect. That doesn't happen.

Sorry typo on the nitrogen, of course it should have been hydrogen. Thermal decomposition (disassociation by the application of heat) of water happens but at temperatures higher than a road tyre is ever likely to reach. The water vapour pressure climb is what we are attempting to avoid with nitrogen.

All of the race cars that I look after run nitrogen, but there's atmospheric air in my road cars' tyres


Cheers
Gary

[NuffNuff]

this video is excellent and definitely worth the watch

[Hilal]

has snake oil written all over it.

[kaanage]

It's not that terrible an idea for people who treat their car as an appliance (nor the spare which hardly anyone pressure checks)

[Martin]

Air is 78% nitrogen and almost 21% oxygen - how much of a benefit are you going get from 100% nitrogen on the street?

It's a real pain having top up at the company you purchased the tyres/nitrogen from and during business hours

You can actually achieve just as good a result as nitrogen by using dry air
Use a coalescing air filter and desiccant dryer system after the compressor (like the spray painters use)
But again - street benefits are low