Nitrogen-Filled Tyres
- Thread starter Phil W
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Holy thread revivals!
My front tyres are always going soft, no idea why, so I went into my local tyre fitter, and they deflated the tyres, cleaned up the rims, put in new valves, and filled all 4 of my wheels with Nitrogen. It's only been a week so far, and I notice zero difference on the road, but they are still round at the top and bottom, so all is well. Only cost me £10 so i'm happy, well I was after i demanded they take off the nasty green valve caps and put back on nice black ones.
Give it a month and i'll check the pressures again, see how they managed to cope.
My front tyres are always going soft, no idea why, so I went into my local tyre fitter, and they deflated the tyres, cleaned up the rims, put in new valves, and filled all 4 of my wheels with Nitrogen. It's only been a week so far, and I notice zero difference on the road, but they are still round at the top and bottom, so all is well. Only cost me £10 so i'm happy, well I was after i demanded they take off the nasty green valve caps and put back on nice black ones.
Give it a month and i'll check the pressures again, see how they managed to cope.
Soldato
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F1 dont seem to use it, as your always hearing them on about the loss of tyre pressure and heat when there behind the pace car
They use nitrogen in aircraft tyres as it volume doesnt change with temperature differences(no where near as much as air anyway). I would imagine thats one of the theories behind using it in car tyres so that the pressure remains fairly constant between hot/cold cycles and varying external temperatures. I have also heard it stops corrosion on the insde of the wheel rim due to not carrying moisture the same as conventional air does.
Yeah, there's a lot of misinformation in this thread too on nitrogen in car tyres.
basically, as said above, there's little point in using it, even on track day cars, since you'd probably change/refill your tyres before most of the claimed benefits are even relevant.
Both oxygen and nitrogen respond similarly to temperature, so the effect of temperature variation on pressure is marginal, and only important in vehicles where tyres are used over long periods or in extreme conditions. What is much more important is the water content of the air in the tyre, which can expand/contract a lot more and cause problems, especially in planes or similar that fly at minus temperatures. Nitrogen is more convenient to use as a dry gas for applications like this, though a lot of professional air compressors have a trap for excess water in the air they provide - I think!
The tyre compounds are less permeable to nitrogen in general, but the effect only really relevant over years compared to months. You should be checking pressures much more regularly than that. Also, the idea of oxygen corroding tyres inside is not unreasonable, but holds little value for on the road, only really in applications like heavy machinery where tyres are used and remoulded for a long time.
Overall it seems like a waste of time, and a money maker for the places that offer it.
This is a summary of what little information/misinformation I could gather. Feel free to disagree, i'd like to hear what other arguments there are for it too.
basically, as said above, there's little point in using it, even on track day cars, since you'd probably change/refill your tyres before most of the claimed benefits are even relevant.
Both oxygen and nitrogen respond similarly to temperature, so the effect of temperature variation on pressure is marginal, and only important in vehicles where tyres are used over long periods or in extreme conditions. What is much more important is the water content of the air in the tyre, which can expand/contract a lot more and cause problems, especially in planes or similar that fly at minus temperatures. Nitrogen is more convenient to use as a dry gas for applications like this, though a lot of professional air compressors have a trap for excess water in the air they provide - I think!
The tyre compounds are less permeable to nitrogen in general, but the effect only really relevant over years compared to months. You should be checking pressures much more regularly than that. Also, the idea of oxygen corroding tyres inside is not unreasonable, but holds little value for on the road, only really in applications like heavy machinery where tyres are used and remoulded for a long time.
Overall it seems like a waste of time, and a money maker for the places that offer it.
This is a summary of what little information/misinformation I could gather. Feel free to disagree, i'd like to hear what other arguments there are for it too.
Soldato
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yeah used in plane tyres as it doesn't expand like air would the higher you fly
Associate
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The purpose of using nitrogen in the track cars was so you could set the pressures cold and they wouldn't rise with the heat from the tyres. 27.7 psi cold - 27.5 psi in the pitlane straight off the track.
Overkill on regular road/track cars though imho.
Overkill on regular road/track cars though imho.
Clearly you didn't read my post properly. The £10 included removal and deflation of my two front wheels, breaking the seal, cleaning up the inside rim of the wheel, then inflating all 4 wheels with nitrogen. So when you look at it that way £10 is bloody cheap!
The new Nissan GT-R is meant to come with Nitrogen filled tyres.
All it does is completely stabilise the pressure inside the tyre during the tyres heat cycles. Nothing more. It is there fore better in this respect than plain air which also has greater seap properties.
Useless for plain road use
Useless if you take your car to the track once a month
Helpful if you have a pure track car
Helpful if you take your car to the track every week
Helpful if you're an idiot
All it does is completely stabilise the pressure inside the tyre during the tyres heat cycles. Nothing more. It is there fore better in this respect than plain air which also has greater seap properties.
Useless for plain road use
Useless if you take your car to the track once a month
Helpful if you have a pure track car
Helpful if you take your car to the track every week
Helpful if you're an idiot
Associate
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It's 78-21 and 1% other stuff (mainly Argon and a tiny bit of CO2).
My inside-rear tyre is like this, I think it's because the alloy rims are corroded (beyond repair), so the air can sneak out. Generally when the tyre gets changed it lasts a week or so before it'll go down, then it needs inflated every two days or so.
O2 (Oxygen) Moleculer mass = 16
N2 (Nitrogen) Moleculer Mass = 14
So its not a bigger molecule.
/edit: Beaten like a ginger step child on his birthday.
KaHn
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Surely that's wrong? It's certainly used in aircraft tyres as it is inert and wouldn't feed a brake fire, i.e. it's self-extinguishing if the brakes catch fire
Nitrogen in defying laws of physics shocker!
)Just because the atom has a higher mass does not mean the molecule or atom is larger. In fact, nitrogen is larger, because of oxygen's increased electronegativity, though it's by a smaller amount than expected as the strength of the N-N triple bond (which is what makes it inert). This only has a small effect on the permeability of the tyre though.
The pressure regulation is only important in extreme situations. Planes fly at high altitudes with low pressure and low temperature, which puts stress on tyres as the pressure difference is large. However, this would be the case with air in the tyre too, nitrogen is just more predictable and uniform as a single substance. It's just more convenient as a dry gas, which is important as water can freeze at the low temperatures planes fly at, which decreases tyre pressure significantly, and if it lands with very low tyre pressure problems can arise.
The whole point of the ideal gas equation is to model gases. Gases in the real world differ from this for many reasons, so saying it's an ideal gas would not account for pressure differences for different materials. It does not take into account changing molecule interactions over distance or the volume of the molecules themselves, which in high pressure environments, like a tyre, is much more significant than in the air around us.
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