nitrogen in street tyres

[intehnet]

niggaz,

mate at work (non performancey car) is getting new tyres and the slick at the tyre shop is trying to sell him nitrogen in his tyres for an extra $30.
i'm aware of the use of nitrogen in racing (used it my self in MGA race car on semis) as it's heat absorption and volume expansion properties are less, thus less fluctation tyre pressures.
question is; is there any point having it in road tyres on a car that'll never be raced?

[ox!gen]

no

[willsy01]

I was under the impression it doesn't slowly leak like normal air does over time?

[intehnet]

no

why?



http://www.toyo.com.au/tech_info11.html

[Shitbreak]

I thought it does slowly leak still overtime (cant see how it wouldnt).

I check and change my pressure every 2 weeks or so. Would get quite expensive if I did this with nitrogen.

I reckon just stick to air as I dont see how it would make a difference to road tyres in terms of handling.

[GTSBoy]

Snake oil at the best of times. Only reason racers use it is that it is cheap and easy to buy a cylinder of it from BOC to take to the track to use in the (magnesium) air tools and in the (magnesium) wheels.

Any other reason touted is pure ricey bullshit.

Air is 79% N2, 21% O2. Tiny traces of the other stuff to fill in the (very small) gap hardly affect the ideallity of the mix. N2 and O2 are just about the same when compared to ideallity anyway.

cheers

[Glenno]

At Queensland Raceway front left tyre on an AU supercar filled with nitrogren starts out at around 21 PSI cold depending on the day and ends up at 30-31 psi hot so i'm calling snake oil as well. The real killer in regard to pressure rise is aparently water in the gas used to fill the tyre. Nitrogen/Bottled Compressed air from BOC is dry where as a normal aircompressor provides air with some moisture content.

[bigmuz]

Rice. I prefer a 79% nitrogen mix in my tyres. Seems to give me that little bit extra performance. Helium would make more sense I reckon

[Glenno]

Velodrome bike racers fill their tyres with helium dont they?

[ox!gen]

Snake oil at the best of times. Only reason racers use it is that it is cheap and easy to buy a cylinder of it from BOC to take to the track to use in the (magnesium) air tools and in the (magnesium) wheels.

Any other reason touted is pure ricey bullshit.

Air is 79% N2, 21% O2. Tiny traces of the other stuff to fill in the (very small) gap hardly affect the ideallity of the mix. N2 and O2 are just about the same when compared to ideallity anyway.

cheers

I knew someone would type out the reasoning for me

[out_in_front]

I think the fact that there is less reatants in the air (ie CO and O2) will make a bit off difference. The oxygen and the CO will usually react with most organic substances (read: rubber) at some stage during the rubbers natural breaking down process. This would also be slighly accellerated due to the warmer temps of the tire and the pressure that is in the tyre.

However as already pointed out there is only 20% oxygen in the air so the most pressure you could theoretically lose would be about 20% then you will pump it up and have an even smaller percentage of oxygen in there. So for racers who have decent temps in their tyre and very soft rubber (most likely more reactive) It could be a bonus but for everyday use I doubt it would do anything except provide wank factor and maybe save 1 trip to the servo to bump up the pressure in the tyres.

[jmac]

It's expansion (probably more due to it not having water content) rate is far more consistent/predictable.

But here's the thing - how is the tyre shop going to actually fill it. Unless they put it inside a chamber and purge the air and replace it with nitrogen and then inflate the tyre, it'll have a few litres of air in there anyway.

This isn't _even_ snake oil, it's worse.

[GTSBoy]

Actually John, you could possibly keep the bead lifted and blow some N2 through the tyre and reduce the amount of air diluting the bottled stuff.

But I bet they don't.

[jmac]

I'd bet money it'd still leave air/moisture in there to some extent. actually scratch that, what I'd as of now like to bet is that aside from the impracticality of them purging air, I'd not be surprised to find them filling the tyres with air period.

[AxGT]

nah - nitrogen is teh shit because they give you those little red valve caps - the caps are the real advantage

[oldcorollas]

I'd bet money it'd still leave air/moisture in there to some extent. actually scratch that, what I'd as of now like to bet is that aside from the impracticality of them purging air, I'd not be surprised to find them filling the tyres with air period.

for purging furnaces, we flow at least 10 times the volume being purged, at low flow rates... but given that a tyre doesn't really have any way to do this, i call shenanigans... unless you get a purge valve fitted

what do the race kiddies do? fill and purge a few times?

[bigmuz]

If the tyre is fitted and contains (uninflated) one atmosphere of air (containing 21% o2) , then filled with nitrogen to say 3 bar (about 45 psi) then the total amount of oxygen is surely down to 7 percent or so.

I guess the advantages are still there, but only 2/3s of what they claim at best

I guess you could sniff it and see if it is actually nitrogen.

[cheaterparts]

we had a customer that had a low loader that carted heavy equipment/machinery and would blow tyres on a regular basis ( heat build up )
on the trailer
so he tryed nitrogen and found that less tyres blew
now that could be the fact that it was dryer it maybe that nitrogen is more stable ?

cheater

[GTSBoy]

It could only be the moisture content. All else is bunk.

[AlexinPerth]

This isn't _even_ snake oil, it's worse.

Yeah, it's like... dilute snake oil.

Alex.

[intehnet]

lol

thanks guys

[bigmuz]

Yeah, it's like... dilute snake oil.

Alex.

Gold mate

[jmac]

If someone _really_ wanted to get ride of the moisture, my gut feeling is the way to do it would be to follow the procedure done for evacuating air conditioning refrigerant pipes/system - reduce it to as close to zero absolute pressure as possible and the water will evaporate and pass out of the system with the last remaining air. So you'd still need a chamber.

that's if you _really_ want to actually do what they are suggesting.

[GTSBoy]

It's actually fairly easy to create dry compressed air. Just need to compress and cool it, then pass it through a dryer to remove drops of water, then pass it through a dessicant cartridge.

A lot more expensive than bottled N2 for big quantities though.

[Lonx]

I'm actually amazed they want extra for nitrogen! Even the local Bob Jane T-Marts around here uses it standard for any car that goes through there getting new tyres, and will top it up for nothing if you want them to (providing you've been there before).

[GTSBoy]

It's normal. Almost every place in Adelaide that I have seen touting nitrogen is doing so at a "premium" price point of $5 per wheel or something.

Fucking ridiculous.

[intehnet]

$7.50 a corner at some random joint in perth my boss got his impreza tyres done..

[Little Erve]

Argon filling ftw

Also helps put out your brakes when they catch fire and melt your rubber

[Bulgogi]

I remember crunching some numbers ages ago for an older version of this thread (before the hackers fucked it to oblivion) and found that the thermal expansion rate of pure nitrogen would've been roughly the same as a normal mixture of air, but just slightly less (maybe 3% percent difference). Pretty much a bee's dick worth of difference.

Easier to nip down to a BP (or wherever a automatic tyre pump with a digital display can be found) every week or two and top up the pressure yourself, IMO.