Nitrogen in Car tyres

[dennis]

Its just a gas the same as air, its not going to behave in a different way at the temperatures tyres usually run at.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Lobster saying something like:

I've got some I can sell you. I'll send a boxful, ok?

[Peter Crosland]

Pure un-diluted bulls***! The crucial thing is to keep the pressures correct.

Peter Crosland

[ARWadsworth]

The bottled stuff is so much better.

Adam

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember The Natural Philosopher saying something like:

How very cosmopolitan.

[Roger Chapman]

Last time I ventured into the realms of half remembered basic physics I managed to get something completely arse about face so take this with a pinch of salt but it seems to me that 1.5 psi is rather too high. Pressure is proportional to temperature so a 10C change in the ambient should produce approximately 1 psi increase in pressure in a tyre at 30 psi and 300K.

[Roger Chapman]

Andrew suggests that if you fill the tyre with N2 O2 will leak in.

QF claim that they introduce some O2. Inflate a flat tyre with N2 and, bingo, you get a tyre filled with N2 with added O2.

[Fredxx]

I follow your calculations until you pull the ratio 11:1 Where do you get the idea that oxygen diffuses through rubber 11 times as much as nitrogen?

[John]

Probably cheaper to buy Nitrogen than to service and insure a compressor.

[js.b1]

Alloy wheels above 16" can easily suffer air pressure loss at the bead area due to corrosion or distortion from potholes.

Alloy wheel width matched to tyre width does seem to greatly increase the number of slow punctures through the sidewall/25%-area. It seems the "square" wheel-tyre width tends to make debris cause a puncture rather than deflect. This is particularly true if driving too close to gutters (out-in-out) or over debris strewn chevrons markings (eg, due to roadworks or people parked on the phone). The phrase "puncture magnet" is not inappropriate.

Would rather spend =A31.50 replacing a tyre at a slightly higher tread depth, or fitting tyre pressure alert caps.

[dennis]

Probably not.. zeolite absorbs the oxygen at about 1.3 atmospheres and then releases it when the pressure drops. So you can concentrate oxygen from air with a simple compressor and a couple of valves, choosing different valve timing will produce oxygen depleted air (~nitrogen) to blow up your tyres. I can't imagine them using one that requires high pressures when they can do it with low pressures.

[dennis]

Why has the tyre got a propeller attached to it?

[Roger Chapman]

Is that a brickbat I see before me?

But hey, how can you see my message to respond when you said only this morning that you were going to "plonk" all the idiots who didn't agree with you.

[george [dicegeorge]]

itd be cheaper if i posted you some condensed in an envelope- just dilute it with air.

[Jerry]

Total and utter con, an externally life expired tyre (such as cracked side walls, cuts, or illegal tread depth) can look brand spanking new on the inside when removed, think about it....

[Andrew Gabriel]

That's the 33:3 ratio above. So the nitrogen has 11 times more pressure on one side of the tyre than the oxygen has on the other side of the tyre.

I said that I've no idea if it is. It needs to be for this theory to work. Frankly, I'd be surprised if it is.

[Jerry]

: : Probably cheaper to buy Nitrogen than to service and insure a compressor. :

Except hat just about every power tool, including the tyre changing machines, in the workshop need to such a compressed air supply...

[Andy Dingley]

"by using it in a mixture with oxygen "

FFS! What sort of mixture do they use, 80/20?

[Dave]

Not actually used to blow out the flames, but used so that the tyre gas did not contain any oxygen that would fan the flames. I have worked on fast jets (mainly Tornado development) for many years and the only time they don't use nitrogen is when the crew are fed from a liquid oxygen container for breathing.

Dave

[ARWadsworth]

I was lead to believe that any dry air mixture would be fine for aircraft tyres. As long as there was no possibility of ice forming inside the tyre at altitude was what mattered.