While having my Toyos fitted yesterday, the fitters offered filling the tyres with a different gas (I *think* Nitrogen?).

My poor language skills meant I didn't really understand the benfits - I guess there's less pressure change related to temps? Any others?

Thanks
Richard

 

Nope, that's the main reason.

 

Mike

nearly all gases will behave the same way.

The behavior of gases is defined by teh gas laws funnily enough, boyles, pressure and charles law.

These are combined in a universal gas law which takes into account that they dont behave like ideal gases. (includes weak attraction between molecules van der waals forces etc).

Aside from this air is 70% nitrogen anyway and 21% oxygen, bit of which will behave almost identically as they are both diamtomic molecules of similar relative atomic mass.

The best reason I can think of for not using it though is that if your car is rolled into a lake by a gangster whilst you are unconcious in the driver seat, you can breathe from the tyres if they have air in them. If they are nitrogen you wont last long, tehrein fooling teh gangsters into thinking you have drowned.

 

Uniflate was originally developed for motor sports and is used by all the Formula 1 Grand Prix teams. It is a nitrogen-based gas and, unlike compressed air, has minimal water vapour and oxygen. It is these two substances that react more to changes in temperature and are more likely to escape from tyres, resulting in deflation.

Distributors claim it will maintain correct tyre pressure for longer than compressed air (it deflates three to four times slower) and over a wider temperature scale. Additionally they claim that due to the minimal water content it will not corrode the tyre from the inside.

They even claim that by maintaining the correct tyre pressure the driver benefits are: optimum grip and handling, extended tyre life, reduced puncture risk and greater fuel efficiency (reducing bills by up to 10%).

Not completely convinced by this hype myself but then again I've not found a local stockist to try it.

Wouldn't even like to hazard a guess at the cost.

Anyone got any practical experience of this in the UK?

 

My father has that in his BMW. We noticed a small improvement in comfort as well as grip. I think it is worth a try.

I don't do it, as I often change the tire pressure and cannot drive everytime to the dealer, although he says that you can fill in air also.

greetings
ric

 

How about helium ?
I here the tyres last longer due to reduced road contact

 

Adam

Great post.. but Mike is right mate. The (dramatically) reduced changes in pressure due to temperature changes is the reason for using Nitrogen.

Cheers

Simon

 

Using lighter-than-air gasses is not such a good idea, mainly because the atomic size of Helium and the like to make them lighter than air means that they are very small and would be much more likely to pass through small hole that air or N2.

Meaning that your tyres will go flatter quicker.

I hope that makes some sense.

Ian

 

Yep, and through the rubber via osmosis.

 

Hehe, Adam had a bit of a "Pat" moment there I believe.

 

The key thing to remember isn't Adam's lecture on the physics of gases (I think I had the same A-level physics book ), but that normal air containts a lot of water vapour which expands when it gets hot. Filling with another gas excludes the water-laden air.

You'd robably be marginally better off with one of the inert gases (helium, neon, argon, etc.) but I think they're expensive compared to nitrogen. Some of the lighter-than-air ones might be a bit strange, but helium has a low molecular mass so would reduce your unsprung weight a bit

 

I was thinking of trying accetalene



Darren