Nitrogen in tyres?

I've heard its good for car tyres to use Nitrogen instead of plain old air as the molecules are larger and therefore the tyre loses less pressure and its pressure is effected less by heat.

Anyone tried it in a car or bike?

[ogden]

http://www.livefrompitlane.com/2011/...g-on-nitrogen/

Unless you're on track and need to accurately predict a temperature/pressure curve to get that last hundredth of a second off the lap time, it's a complete waste of time.

My mate raced with them (fridge engineer so got the gas for nowt) but he said it was more hassle carting the gas cylinder round than it was worth.

The benefits have nowt to do with molecule size, don't forget air is ~70% nitrogen.

The benefit come from the fact that there is water vapour / moisture in regular air where as the nitrogen in a tank doesn't and the water vapour is the part that expands a lot under heat. If you were to bottle regular air and remove the moisture the effects would be identical.

[Sid Squid]

There are a number of possible advantages of nitrogen; pressure loss reduced, pressure should be more temperature stable, reduced rim corrosion, theoretically cooler running and longer tyre life. Many of these are theoretical and, to say the least, disputed, the biggest problem being purity, air is 80%ish nitrogen and 20%ish oxygen, (very roughly speaking - don't no-one go getting fussy already), the general feedback is that the stuff offered for tyres in many places is not pure - I've heard many different estimated figures as to the purity, the most common being about 5-7%ish oxygen.

This is most unlikely to offer any of the possible benefits of pure nitrogen so I rather doubt it's worthwhile, and any theoretical saving on tyre life is likely to be greatly outweighed by the cost.

A quote from the Kwik Fit web site:

Have your tyres filled with Nitrogen and increase tyre life by up to 25%, improve road holding and handling and increase fuel economy by up to 5%!

Filling your tyres with nitrogen may seem odd but that's exactly what motor sport and aviation professionals have been doing for years. Nitrogen is completely safe for use in tyres. By using it in a mixture with oxygen to inflate your tyres the theory is that it's possible to negate the issue of slow deflation, due to the larger nitrogen molecules taking longer to migrate from the tyre into the atmosphere through the tyre wall.

Having a tyre that does not deflate means you will improve fuel consumption and will probably improve safety standards too. It's not yet standard practice but Nitrogen could well be here to stay as a result.

Wondered if anyone else has tried it.

[ogden]

For your purpose, it's snake oil. Simple as that.

[Sid Squid]

Originally Posted by Kwik-Fit

By using it in a mixture with oxygen to inflate your tyres

By using it in a mixture with oxygen it would be err... air.

What utter, utter cobblers that statement from Kwik-Fit is.

I went for nitrogen last time I got new tyres on the Volvo. Probably mostly marketing guff, but with two useful features:
1. I'm a bit pants at checking the tyre pressures and topping up as often as I should. If I pop into ATS, they are now obliged to check and top up whenever required. At no charge. For the life of the tyre.
2. When the wheels are clean, the green dust caps look cool (which is why I haven't had the bike done because, on the blue bike, they'd look s*&t!)

If the oxygen diffuses out faster than nitrogen then over time as you top up your tyres you would end up increasing the nitrogen partial pressure until, over many top ups, there would be no oxygen left...

If you really wanted to slow diffusion and stop corrosion then argon would be ideal... Higher specific heat capacity would give a more stable tyre temperature but the unsprung mass would also increase.

ol playing devil's advocate is fun