Nitrogen in tyres
Discussion
I've been meaning to source someone who offers Nitrogen inflation for tyres, but it seem to keep slipping down the list, overtaken by far more urgent problems!
Anyway, I had my Costco magazine through the post today, and there's an article in there about the use of Pure Nitrogen in tyres.
In short Costco tyre fitting centres will now be using Nitrogen to fill tyres, and, if you have a valid Costco membership, then they'll replace the air in your tyres with Pure Nitrogen for free.
Advantages seem to be:
Less corrosion because there's no moisture in the Nitrogen
Slower rate of pressure loss - due to molecule size apparently!
Stable pressure regardless of temperature.
Got to be worth a go.
Tim
Anyway, I had my Costco magazine through the post today, and there's an article in there about the use of Pure Nitrogen in tyres.
In short Costco tyre fitting centres will now be using Nitrogen to fill tyres, and, if you have a valid Costco membership, then they'll replace the air in your tyres with Pure Nitrogen for free.
Advantages seem to be:
Less corrosion because there's no moisture in the Nitrogen
Slower rate of pressure loss - due to molecule size apparently!
Stable pressure regardless of temperature.
Got to be worth a go.
Tim
How about helium instead to make it lighter 
Didn't we have a huge fight about this already? 
I seem to recall the view was that:
a) The only reason it's "dry" is because it's processed. Air could be the same but we just don't bother. How much corrosion do you get on a set of alloys?
b) 70%ish of air is Notrogen, so how is it going to make a significant difference to either pressure loss or temperature impact?
Mind you, it's free and it SOUNDS cool!
I seem to recall the view was that:
a) The only reason it's "dry" is because it's processed. Air could be the same but we just don't bother. How much corrosion do you get on a set of alloys?
b) 70%ish of air is Notrogen, so how is it going to make a significant difference to either pressure loss or temperature impact?
Mind you, it's free and it SOUNDS cool!
I have been using it for years now. Before with normal air i had to check and fill the tyres about once a month, and yes, that was with different tyres. After a fill with nitrogen the pressure stayed constant for about 6 months before going ever so slightly down. Over here they advice it for trackuse, the pressure goes up less with nitrogen than with air when the tyre warms up, and for caravans that stay in storage during the winter.
So for me it does work.
So for me it does work.
I've had nitrogen in my tyres on the TVR and my Mondeo for over a year. Pressure drops very slowly indeed but whenever I've gone for a top-up (free if you produce the recept for the tyre) I've had to queue for the compressor.
I was told that if there's a high water content, when the tyres get very hot, the water boils and increases the pressure considerably. However, talking to a tyre professional I was told that it was a load of rubbish.
After reading the lack of water was more to do with the pump type than the gass type, I asked the chap at the tyre place if it was true and he reckoned that if I could find a commercial compressor locally that supplies dry air then I was a genius. I'm not, it seems, a genius.
I was told that if there's a high water content, when the tyres get very hot, the water boils and increases the pressure considerably. However, talking to a tyre professional I was told that it was a load of rubbish.
After reading the lack of water was more to do with the pump type than the gass type, I asked the chap at the tyre place if it was true and he reckoned that if I could find a commercial compressor locally that supplies dry air then I was a genius. I'm not, it seems, a genius.
Sorry to get all Geeky, but I do work in the oil and gas industry for my sins.
In 1702 a chap called Amontons, discovered that gas (any pure gas) will expand in a linear fashion as the temperature is increased! Boils Law and Charles Law are most quoted if your interested.
Amontons found thet from 0DegC to 100DegC all gasses will expand to increase the pressure by 33%.
At my work we use the molecular difference in our nitrogen (N2) unit to get rid of the oxygen (O2), it squeezes the heated O2 through a membrane (like your tyre wall).
We also use a lot of compressed air, and this is run through industry standard drying units to get rid of the moisture.
Basically silica gell beads, but it does cost money to do this (extra air bleed). Which is why the local garage won't bother.
So there would be a slight advantages to using dry N2 to increase tyre stability.
Steve
In 1702 a chap called Amontons, discovered that gas (any pure gas) will expand in a linear fashion as the temperature is increased! Boils Law and Charles Law are most quoted if your interested.
Amontons found thet from 0DegC to 100DegC all gasses will expand to increase the pressure by 33%.
At my work we use the molecular difference in our nitrogen (N2) unit to get rid of the oxygen (O2), it squeezes the heated O2 through a membrane (like your tyre wall).
We also use a lot of compressed air, and this is run through industry standard drying units to get rid of the moisture.
Basically silica gell beads, but it does cost money to do this (extra air bleed). Which is why the local garage won't bother.
So there would be a slight advantages to using dry N2 to increase tyre stability.
Steve
Derek Smith said:
I asked the chap at the tyre place if it was true and he reckoned that if I could find a commercial compressor locally that supplies dry air then I was a genius. I'm not, it seems, a genius.
got a local dive shop near you? that would make you a genius as the compressed air delivered by them is dry (not sure if they would let you pump the tires up on it though) Dry air is used in Scuba tanks as well, so they dont decay from the inside of the bottle. Clean air, as long as the exhaust fumes don't get fed back into the intake of the compressor. If they do its headache time and the bottle needs cleaning.
You could use a Scuba tank to fill/top up your tyres. Some shops fill up the tanks these days free of charge.
You could use a Scuba tank to fill/top up your tyres. Some shops fill up the tanks these days free of charge.
The air in scuba tanks is not dry, but it does have some of the water removed.
As a gas expands it cools. This can form condensation which can then freeze to ice. This will lock up valves and block pipes. Not good when you have nothing else to breath.
However, if you remove the water entirely, the air would dry the respiratory tract causing breathing difficulties. Worst dry throat you could imagine, swelling, eventual dehydration of the whole body.
The moisture content of air compressed for breathing is therefore controlled to within an acceptable dew point range.
As a gas expands it cools. This can form condensation which can then freeze to ice. This will lock up valves and block pipes. Not good when you have nothing else to breath.
However, if you remove the water entirely, the air would dry the respiratory tract causing breathing difficulties. Worst dry throat you could imagine, swelling, eventual dehydration of the whole body.
The moisture content of air compressed for breathing is therefore controlled to within an acceptable dew point range.
Steve E said:
Sorry to get all Geeky, but I do work in the oil and gas industry for my sins.
In 1702 a chap called Amontons, discovered that gas (any pure gas) will expand in a linear fashion as the temperature is increased! Boils Law and Charles Law are most quoted if your interested.
Amontons found thet from 0DegC to 100DegC all gasses will expand to increase the pressure by 33%.
At my work we use the molecular difference in our nitrogen (N2) unit to get rid of the oxygen (O2), it squeezes the heated O2 through a membrane (like your tyre wall).
We also use a lot of compressed air, and this is run through industry standard drying units to get rid of the moisture.
Basically silica gell beads, but it does cost money to do this (extra air bleed). Which is why the local garage won't bother.
So there would be a slight advantages to using dry N2 to increase tyre stability.
Steve
So - if all gases expand by a third .. why use nitrogen ?In 1702 a chap called Amontons, discovered that gas (any pure gas) will expand in a linear fashion as the temperature is increased! Boils Law and Charles Law are most quoted if your interested.
Amontons found thet from 0DegC to 100DegC all gasses will expand to increase the pressure by 33%.
At my work we use the molecular difference in our nitrogen (N2) unit to get rid of the oxygen (O2), it squeezes the heated O2 through a membrane (like your tyre wall).
We also use a lot of compressed air, and this is run through industry standard drying units to get rid of the moisture.
Basically silica gell beads, but it does cost money to do this (extra air bleed). Which is why the local garage won't bother.
So there would be a slight advantages to using dry N2 to increase tyre stability.
Steve
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