Car tyres

[AdrianF (Adrian)]

Ok the subject might not be the most appropriate subject for this forum, but with all the expertise on here I thought I would ask.
I bought myself a Pajero on Saturday and have had a call from the previous owner telling me that the tyres have been pumped up with nitrogen not air. What's the advantages of this? I have googled it and there are so many conflicting ideas. As there are a few motoring enthusiasts on this forum I thought I would ask

Adrian

[ZeroID (Brent)]

Air is mostly (78%) nitrogen. Pure 100% nitrogen though is dry, no moisture so less expansion under heat. This is probably very useful in a high performance tyre\speed situation where tyre temperature can get really quite high but for 4wd and the like not of much use to be honest. Track cars like to go that way, your big V8's on Bathurst, F1, production racers at the top end etc..
Says the previous owner was a bit of a purist possibly. Don't know how hard it would be to find Nitrogen supplies in Aus. Your local garage certainly won't have it online.

[GeoffW1 (Geoff)]

Hi,

You can find a lot of opinion, like this

http://news.drive.com.au/drive/motor...526-1f4vb.html

that it is a marketing scam, for the needs of the average suburban motorist.

Cheers

[AdrianF (Adrian)]

From what I can make out if I was traveling at 200k plus an hour it might be worth it but I am not so I will change slowly back to air

Adrian

[Barrykgerdes]

When I was working years ago on HMAS Melbourne they had a plant for producing dry nitrogen for the airplane ties. It was very handy because we used to put dry nitrogen in the aerial coupler for our transmitters.

Interesting side light to this was we pressurised these aerial couplers to about 15 lb/sq in and wonderd why thy burnt out. The reason
was the protective spark gap on the network would break down at 1 or 2 psi and fail safe. However pressurising to 15 PSI almost doubled the breakdown voltage. As a result the coil caught fire instead of shutting the system down. After this we reset the spark gap and limited the pressurization to 6 PSI. No more burn outs.

Barry

PS Getting Dry nitrogen was never a problem when in the field I could always get it from the nearest CIG depot

[AstralTraveller (David)]

Maybe it's not much use in your tyres but dry nitrogen would be great in your OTA! Cylinders of high purity N are pretty cheap and sets of regulators aren't too too expensive, so owners of premium refractors or catadioptics might even consider this. Owner of truss tube newts wouldn't see any benefit.

[AstroFlyer (Arek)]

Originally Posted by ZeroID

Says the previous owner was a bit of a purist possibly. Don't know how hard it would be to find Nitrogen supplies in Aus. Your local garage certainly won't have it online.

Actually it is quite easy to find suppliers.
I bought new tyres for my wife's car & for $40 extra got 5 year tyre warranty which included, amongst other things, free nitrogen for the life of tyre.
Maybe it's a coincidence, but the tyre pressure seems to much more stable now.

[Barrykgerdes]

Yes Dry nitrogen is relatively plentiful. It is a by-product of the fractional distillation of Oxygen. This method also ensures it is dry as all the water comes out at its freezing point as the temperature is lowered.

Barry

[TheDecepticon]

I am a career mechanic (30 years) and now work for our states motoring club, the RAA, as a Technical Advisor. This is something we have done some minor research into, but more is coming, like the percieved benefits of window tinting.

For standard road cars, there is no real need to use nitrogen in your tyres. There is no research performed by credible organizations that it is of any benefit to the average motorist.

If you need to pump your tyres up some where, are you going to wait until the tyre shop opens on Monday so you can go back to them to get it filled, or are you going to pump it up from the tyre pump at the fuel outlet and get on with your life?

Unless the tyre is completely evacuated and sucked down to a shrivelled up black rubbery thing, your going to have normal atmospheric air mixed in there anyway therefore bringing you back to square one.

In most cases, it is a sell up from the tyre shop, just another way of helping you part with your hard earned dollaros.

[Barrykgerdes]

Originally Posted by TheDecepticon

Unless the tyre is completely evacuated and sucked down to a shrivelled up black rubbery thing, your going to have normal atmospheric air mixed in there anyway therefore bringing you back to square one.

.

That is a good point. When we refilled the Aerial couplers wth dry nitrogen. The procedure was to run the nitrogen in and let the air out the relief hole. This process was continued for 5 minutes, long enough to purge 99% of the old air out.

5 minutes of this used up enough nitrogen to fill an awful lot of containers.

Barry

[bartman (Bart)]

Ummm just a word of caution.......not that it might apply here, but just in case.
Nitrogen displaces oxygen.
In a confined space that could be a problem if the bottle has a leak .
Walk into a room that is filled with Nitrogen and you will suffocate ( unless there is sufficient ventilation of course).
Just something I learned whilst working on Varanus Island...... ( drying out pipes)
Bartman

[wasyoungonce (Brendan)]

This fad started to mimic Aircraft types being filled with Nitrogen.

Aircraft tyres filled with nitrogen because a compressed air mixture may cause a wheel fire when (if) the tyre slips against the hub causing high temperature friction fire. This has happened and why Aircraft tyres have slip markers on the tyre/rim and fuse-able plugs. Thus also the introduction & use of nitrogen gas to fill the tyres and also because most flight lines have a portable nitrogen rig available.

Motor vehicle tyres cannot get to the same pressures and loads of aircraft tyres and it is not needed and it is a gimmick for business to make a buck!

Don't get taken...as said air is 78% nitrogen so if you pay for nitrogen in your tires ask for 22% nitrogen and have them fill the rest of nitrogen (78%) from the free air.

edit:
most nitrogen available from "tyre places" is not high purity nitrogen (probably 96% purity) and indeed this is not moisture reduced so it does contain some moisture.

[AstralTraveller (David)]

Originally Posted by bartman

Ummm just a word of caution.......not that it might apply here, but just in case.
Nitrogen displaces oxygen.
In a confined space that could be a problem if the bottle has a leak .
Walk into a room that is filled with Nitrogen and you will suffocate ( unless there is sufficient ventilation of course).
Just something I learned whilst working on Varanus Island...... ( drying out pipes)
Bartman

I work with liquid nitrogen and so am quite aware of the dangers. It's worth being aware that nitrogen asphixiation produces no symptoms .... zero zilch. You do not fell drowsy, you do not feel short of breath, nor tired. There is no warning. You simply collapse and if no one rescues you within a couple of moments you will die. One person even died in the open air where cold nitrogen ponded in a pit.

In a 'normal' asphixiation situation the symptoms are produced by the build up of CO2 in the blood - not by the lack of oxygen. In this situation however there is no build up of CO2, it can vent normally. So you feel nothing.

During the safety induction I pound into every student's head that if there is ever a bulk leak of liquid nitrogen in the lab (we have 50l and 35l dewars) everyone is to leave immediately. No ifs, no buts, no wait till I finish this. (BTW I have absolutely no reason to believe we would ever have a dewar fail, but if it did there is no time for debate.)

[AdrianF (Adrian)]

Well this wont be a problem after today. Had a tyres side wall split and I cant get a replacement tyre the same as the others, American brand tyre company went to the wall in GFC, so have opted to put new tyres all round to be safe. Will get them to fill with good old air.

Adrian

[Omaroo (Chris Malikoff)]

Adrian - it's a 4WD!!!! If you intend to take it properly off road you should be airing down (release pressure to around the 16lb mark or less depending on terrain) for extra traction when required anyway. It's why most 4WDers carry on-board air compressors. Bye bye stupid nitrogen. The first time you popped a bead on a rough track or sand it'd be gone anyway.

[AdrianF (Adrian)]

I agree it's a 4x4. The previous owner put the nitrogen in the tyres I wouldnt have bothered.

Adrian