jfm

Anyone have any experience of this? Is it worth it, or is it perfectionism-too-far? I'm in Europe where 100mph+ running for hours on end is common, and the tires do get warm. Anyone used nitrogen, even in race cars? Anyone know of a source of nitrogen - high perf tire shops maybe?. The cut/past below gives more background. It's from UK so spelling is "tyres" :-)

http://www.bbc.co.uk/science/science...ingtyres.shtml

"Nitrogen is a very unreactive gas. If you fill a tyre with dry nitrogen gas, it is possible to predict how much it will expand as the tyre heats up from friction with the road. Air on the other hand is an unpredictable beast. While its composition is always the same, consisting of 76% nitrogen and about 20% oxygen, the amount of water in it can change from minute to minute and this water makes the expansion of air very unpredictable.

The height of a racing tyre is critical to a couple of millimetres. If the pressure in a tyre is too high the car will be difficult to steer and if it is too low the car may scrape the track, so race engineers need to know exactly how much the gas in a tyre will expand during a race. In the extreme situation of a crash the fact that nitrogen expands less than oxygen when heated means there is less chance of the tyre exploding during a fire. Tyres can explode with the force of a dynamite detonation, which increases the risk already faced by rescue crews.

This is the high performance end of the spectrum, but nitrogen is also used in the tyres of more every day vehicles. Long distance lorries often use it as water in air oxidises the rubber in tyres causing them to corrode. Over longer periods gas also diffuses out of tiny pores in rubber tyres. As a nitrogen molecule is larger than an oxygen molecule it leaks out of tyres three times slower than air, which maintains tyre pressure and therefore tread wear. All in all, using nitrogen in tyres can more than double their lifespan, although for the flimsy racing tyre which needs changing several times in a race nothings going to make that much difference."

Ends

jfm

Answered my own question. It's available all over SE England, and very cheap (about $2 per wheel). I think I'll try some.

http://www.merityre.co.uk/why_nitrogen.htm

Jim Dolan

Alright now you've gone to far.

I'll have to check with the Ahmad at the Quick and Serve to see if they have it on tap.

Should we put a TECH in front of this post?

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pmiranda

We already had this discussion a couple weeks ago. I believe the conclusion was that the water vapor is what really gets you, not the oxygen, so you really just need to use a compressor with a water trap.

greg

Look - pressure and temperature are inextricably related. One goes up, so does the other. the racers (and we're talking ONLY the guys at F1 level or close, with $M+ budgets) spend money on nitrogen because it is moisture free and thus its expansion can be predicted. However I challenge anyone on this board to feel a 1 lb difference, let alone a 0.1 lb difference, in our tires.

Just use air.

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Lonman

99.999999% of people would never even feel the difference...

Bugatti

But mentally....

I know my car drives better after I wash it.

tfung

I agree... you won't feel any differences, and the difference of a one or two psi on a street car does not matter at all...

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CASEY1

Hope I don't get flamed for this but I disagree with Greg. My brother races Nascar type stock cars in the midwest and they ALL use nitrogen in their tires. Many of the racers also have dryers to remove any moisture in the tires. For example: if my brother started a race on regular air in his tires; the right side tires would grow 16lbs within 30 laps!! With nitrogen the same tires would only grow 6-8 lbs. By using dried nitrogen the tires would only grow 2-3 lbs. Also, on a radial racing tire, a 1lb increase in air pressure is equal to 25lb increase in spring rate!Now imagine your tires growing 10-15 lbs when you go to a road coarse and run your M5 at a spirited pace! Sorry Greg 1 lb does make a difference. Also remember when tires are mounted, the lube used to mount your tires contains moisture.The only way to minimize moisture in your tires is to dry mount the tires, and use dried nitrogen. You don't need $M+ budgets to use nitrogen. Driers cost 400-500 dollars.

thompsw

Another option is to use air from a scuba tank, which is filled with very dry air. I have such a rig, but have not played around to see if I notice the difference in filling with dry air.