Tosh about Nitrogen in Sprint
Discussion
I apologise to those who have not read the article, but I thought I'd reply to some of the points made about how wonderful it is to spend extra cash filling your tyres with N2.
Firstly N2 is dryer than air - rubbish!! Dry N2 is dryer than 'normal' air granted, however simply dry your air and you get the same water vapour content. I've got an air compressor in my lab that supplies perfectly dry air to various bits of kit - it's just a case of filtering. These filters require replacing every 6 months so I guess that's too much effort for the average garage forecourt - I suspect that compressors separating the N2 are more regularly serviced hence the drying filters are changed. If you're concerned about water in your tyres my advice is to fill up on a low humidity day.
Secondly the bleed rate of nitrogen is slower than air - hmmm! Gas will always want to flow from a high pressure to a low one obviously. The rate at which it does so depends on the pressure difference, the medium between the high and low pressure and the size of the gas molecules. Put simply it's like pushing balls through a net - the harder you push (pressure diff) and the smaller the balls (molecules) then the faster the flow rate is. Sorry to state the obvious but last time I looked nitrogen and oxygen were next door neighbours in the periodic table and with a similar bonding regime to form N2 and O2 the size difference of the molecules is likely to be negligible. You also have to remember that air is 78% nitrogen anyway so the scope for this apparent effect only effects 22% of the gas in the tyre anyway.
Firstly N2 is dryer than air - rubbish!! Dry N2 is dryer than 'normal' air granted, however simply dry your air and you get the same water vapour content. I've got an air compressor in my lab that supplies perfectly dry air to various bits of kit - it's just a case of filtering. These filters require replacing every 6 months so I guess that's too much effort for the average garage forecourt - I suspect that compressors separating the N2 are more regularly serviced hence the drying filters are changed. If you're concerned about water in your tyres my advice is to fill up on a low humidity day.
Secondly the bleed rate of nitrogen is slower than air - hmmm! Gas will always want to flow from a high pressure to a low one obviously. The rate at which it does so depends on the pressure difference, the medium between the high and low pressure and the size of the gas molecules. Put simply it's like pushing balls through a net - the harder you push (pressure diff) and the smaller the balls (molecules) then the faster the flow rate is. Sorry to state the obvious but last time I looked nitrogen and oxygen were next door neighbours in the periodic table and with a similar bonding regime to form N2 and O2 the size difference of the molecules is likely to be negligible. You also have to remember that air is 78% nitrogen anyway so the scope for this apparent effect only effects 22% of the gas in the tyre anyway.
Edited by James45LW on Monday 10th July 23:01
Nitrogen has a more stable and predictable rate of expansion, which is noticeable when tracking on the edge etc. Its not just a consumer marketing ploy.
I had my tyres filled with the stuff and I went out on a heated run, came back and checked the pressure, it read 0.5 higher than when cold.
Do it with air and you will easily notice 2psi difference at the rears and upto 3 at the front (on front engined cars)
My 2pence worth.
But be careful, very rarely will you find a place that gives you the real deal, most that offer Nitrogen filling are actually running a bullshit stake.
I had my tyres filled with the stuff and I went out on a heated run, came back and checked the pressure, it read 0.5 higher than when cold.
Do it with air and you will easily notice 2psi difference at the rears and upto 3 at the front (on front engined cars)
My 2pence worth.
But be careful, very rarely will you find a place that gives you the real deal, most that offer Nitrogen filling are actually running a bullshit stake.
The ideal gas law, boyle's law and Charles's law all tend to disagree with your statement - i.e. the rate of expansion of a gas is directly proportional to its temperature. You're right in saying nitrogen and air will expand at different rates but the expansions will be linear. The difference in rate will come down to the difference in the volume occupied by 1 mole of the respective gases - which I suspect is minimal between pure N2 and air.
Did you measure the tyre temperatures after each run? Perhaps you were trying harder when filled with air?
Did you measure the tyre temperatures after each run? Perhaps you were trying harder when filled with air?
SXS said:
Nitrogen has a more stable and predictable rate of expansion, which is noticeable when tracking on the edge etc. Its not just a consumer marketing ploy.
I had my tyres filled with the stuff and I went out on a heated run, came back and checked the pressure, it read 0.5 higher than when cold.
Do it with air and you will easily notice 2psi difference at the rears and upto 3 at the front (on front engined cars)
My 2pence worth.
But be careful, very rarely will you find a place that gives you the real deal, most that offer Nitrogen filling are actually running a bullshit stake.
I had my tyres filled with the stuff and I went out on a heated run, came back and checked the pressure, it read 0.5 higher than when cold.
Do it with air and you will easily notice 2psi difference at the rears and upto 3 at the front (on front engined cars)
My 2pence worth.
But be careful, very rarely will you find a place that gives you the real deal, most that offer Nitrogen filling are actually running a bullshit stake.
if you are only seeing a 2 psi increase Ash...you ain't tryin'!
should see ATLEAST +6 psi if you are working the tyres (car)
no wonder you need 1000bhp
andy
monster
I read the article in Sprint and thought "that's not quite right" but neither James nor Ash have got it quite right
to be continued
black circles.com said:
Why fill my tyres with Nitrogen?
Why would you want to do this? The benefits of Nitrogen filling are as follows:
Improved comfort of ride
Improved safety
Increased fuel savings
Improved life of tyre
Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).
The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.
Why would you want to do this? The benefits of Nitrogen filling are as follows:
Improved comfort of ride
Improved safety
Increased fuel savings
Improved life of tyre
Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).
The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.
to be continued
Edited by profstoff on Tuesday 11th July 07:19
...but it's not just the size of the molecule that determines the permeation rate...
So,even though the molecules are the same size, oxygen will permeate faster. This is how small scale N2 generators work.
air liquide said:
Nitrogen membranes separate gases by the principle of selective permeation across the nitrogen membranes wall. For nitrogen polymeric membranes, the rate of permeation of each gas is determined by its solubility in the nitrogen membrane material, and the rate of diffusion through the molecular free volume in the nitrogen membrane wall. Gases that exhibit high solubility in the nitrogen membranes, and gases that are small in molecular size, permeate faster than larger, less soluble gases.
So,even though the molecules are the same size, oxygen will permeate faster. This is how small scale N2 generators work.
Edited by profstoff on Tuesday 11th July 07:21
Guillotine said:
SXS said:
Nitrogen has a more stable and predictable rate of expansion, which is noticeable when tracking on the edge etc. Its not just a consumer marketing ploy.
I had my tyres filled with the stuff and I went out on a heated run, came back and checked the pressure, it read 0.5 higher than when cold.
Do it with air and you will easily notice 2psi difference at the rears and upto 3 at the front (on front engined cars)
My 2pence worth.
But be careful, very rarely will you find a place that gives you the real deal, most that offer Nitrogen filling are actually running a bullshit stake.
I had my tyres filled with the stuff and I went out on a heated run, came back and checked the pressure, it read 0.5 higher than when cold.
Do it with air and you will easily notice 2psi difference at the rears and upto 3 at the front (on front engined cars)
My 2pence worth.
But be careful, very rarely will you find a place that gives you the real deal, most that offer Nitrogen filling are actually running a bullshit stake.
if you are only seeing a 2 psi increase Ash...you ain't tryin'!
should see ATLEAST +6 psi if you are working the tyres (car)
no wonder you need 1000bhp
andy
monster
lol
Damn it, I've been suss'd,
But 175mph I thought would have been enough?
must have been a cold day.profstoff said:
I read the article in Sprint and thought "that's not quite right" but neither James nor Ash have got it quite right
to be continued
black circles.com said:
Why fill my tyres with Nitrogen?
Why would you want to do this? The benefits of Nitrogen filling are as follows:
Improved comfort of ride
Improved safety
Increased fuel savings
Improved life of tyre
Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).
The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.
Why would you want to do this? The benefits of Nitrogen filling are as follows:
Improved comfort of ride
Improved safety
Increased fuel savings
Improved life of tyre
Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).
The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.
to be continued
Edited by profstoff on Tuesday 11th July 07:19
Naaa, I've had 32psi all round in my daily ride for yonks, every odd month I check, and its still 32psi, and its not nitrogen in there. So Blackcircles theory goes out the window there! Most tyres now use a multi-layered nylon and dual steelbelt woven thingybob with MORE rubber on the sidewalls and a thick coating of something on the inside. A good rim will hold the rubber well, its the chav stylee wheels and the cheaper alloys that cause problems IMO.
Honestly, over 8 months, and never lost a single PSI on either front or back!
. . . points made about how wonderful it is to spend extra cash filling your tyres with N2.
To be fair, I did not state that it is a great idea. In fact, I highlighted one problem I had experienced. Further, no extra cash was involved. It was a no-cost option.
Firstly N2 is dryer than air - rubbish!! Dry N2 is dryer than 'normal' air granted, however simply dry your air and you get the same water vapour content. I've got an air compressor in my lab that supplies perfectly dry air to various bits of kit - it's just a case of filtering. These filters require replacing every 6 months so I guess that's too much effort for the average garage forecourt - I suspect that compressors separating the N2 are more regularly serviced hence the drying filters are changed. If you're concerned about water in your tyres my advice is to fill up on a low humidity day.
My information (one source) is that pure nitrogen is able to carry proportionately less water vapour than air and is easier to 'clean'. Further, whilst you are lucky enough to have a compressor with a water filter, the one I bought at a local motor factors does not. I'm not sure about the benefits of topping up on a low humidity day, surely that would be a difference in degree, not kind.
Secondly the bleed rate of nitrogen is slower than air - hmmm! Gas will always want to flow from a high pressure to a low one obviously. The rate at which it does so depends on the pressure difference, the medium between the high and low pressure and the size of the gas molecules. Put simply it's like pushing balls through a net - the harder you push (pressure diff) and the smaller the balls (molecules) then the faster the flow rate is. Sorry to state the obvious but last time I looked nitrogen and oxygen were next door neighbours in the periodic table and with a similar bonding regime to form N2 and O2 the size difference of the molecules is likely to be negligible. You also have to remember that air is 78% nitrogen anyway so the scope for this apparent effect only effects 22% of the gas in the tyre anyway.
Basing your conclusions on the nearness of oxygen and nitrogen to one another on the periodic table is, perhaps, a little simplistic. I checked two different sources and was told that there is a significant difference in the leakage rates.
As I said earlier, nitrogen was a no-cost option and, despite reservations, I thought I'd give it a go. I'm no specialist in tyre dynamics so I checked all the information with those who are. The article could, of course, be misleading and I'd be only too pleased for someone to correct any errors. However I spoke with technical experts who have no axe to grind in the matter or nitorgen filling and at the moment will follow their advice.
There will be a small follow-up article in this month's Sprint with regards to nitorgen filling. If anyone has any practical experiences I'd be very grateful if you could share them with me at:
editor@tvrcc.com
Derek
To be fair, I did not state that it is a great idea. In fact, I highlighted one problem I had experienced. Further, no extra cash was involved. It was a no-cost option.
Firstly N2 is dryer than air - rubbish!! Dry N2 is dryer than 'normal' air granted, however simply dry your air and you get the same water vapour content. I've got an air compressor in my lab that supplies perfectly dry air to various bits of kit - it's just a case of filtering. These filters require replacing every 6 months so I guess that's too much effort for the average garage forecourt - I suspect that compressors separating the N2 are more regularly serviced hence the drying filters are changed. If you're concerned about water in your tyres my advice is to fill up on a low humidity day.
My information (one source) is that pure nitrogen is able to carry proportionately less water vapour than air and is easier to 'clean'. Further, whilst you are lucky enough to have a compressor with a water filter, the one I bought at a local motor factors does not. I'm not sure about the benefits of topping up on a low humidity day, surely that would be a difference in degree, not kind.
Secondly the bleed rate of nitrogen is slower than air - hmmm! Gas will always want to flow from a high pressure to a low one obviously. The rate at which it does so depends on the pressure difference, the medium between the high and low pressure and the size of the gas molecules. Put simply it's like pushing balls through a net - the harder you push (pressure diff) and the smaller the balls (molecules) then the faster the flow rate is. Sorry to state the obvious but last time I looked nitrogen and oxygen were next door neighbours in the periodic table and with a similar bonding regime to form N2 and O2 the size difference of the molecules is likely to be negligible. You also have to remember that air is 78% nitrogen anyway so the scope for this apparent effect only effects 22% of the gas in the tyre anyway.
Basing your conclusions on the nearness of oxygen and nitrogen to one another on the periodic table is, perhaps, a little simplistic. I checked two different sources and was told that there is a significant difference in the leakage rates.
As I said earlier, nitrogen was a no-cost option and, despite reservations, I thought I'd give it a go. I'm no specialist in tyre dynamics so I checked all the information with those who are. The article could, of course, be misleading and I'd be only too pleased for someone to correct any errors. However I spoke with technical experts who have no axe to grind in the matter or nitorgen filling and at the moment will follow their advice.
There will be a small follow-up article in this month's Sprint with regards to nitorgen filling. If anyone has any practical experiences I'd be very grateful if you could share them with me at:
editor@tvrcc.com
Derek
James45LW said:
The ideal gas law, boyle's law and Charles's law all tend to disagree with your statement - i.e. the rate of expansion of a gas is directly proportional to its temperature.
Although it's important to note that all three laws (I thought the first one was the "gas pressure law" actually) only apply to ideal gases, of which there are none. The closest things are the noble gases (He, Ne, Ar, Xe, etc.)
My take on it (for what it's worth) is that it's easier to buy N2 dryer than it is to filter compressed air! Nobody changes filters in compressors in industry let alone on the garage forecourt!
As air is mostly N2 anyway there's next to no significant difference for road applications and for competition use the only benefit I can think of is it might conduct heat better (immeasurably!)
I read the article with interest and found it useful and informative. I did not find it misleading in any way. It reinforced my idea that it's not worth paying for but if it were offered FOC I would not turn it down.
I have used both N2 and dry compressed air for cooling/keeping clean high power laser optics in industry and the only differences noted were that due to poor maintenance you always get water, oil, crap in compressed air whereas N2 comes clean and dry straight out of the bottle.
For filling my tyres at a garage I tend to blow the airline out a bit to clear out any standing water.
As air is mostly N2 anyway there's next to no significant difference for road applications and for competition use the only benefit I can think of is it might conduct heat better (immeasurably!)
I read the article with interest and found it useful and informative. I did not find it misleading in any way. It reinforced my idea that it's not worth paying for but if it were offered FOC I would not turn it down.
I have used both N2 and dry compressed air for cooling/keeping clean high power laser optics in industry and the only differences noted were that due to poor maintenance you always get water, oil, crap in compressed air whereas N2 comes clean and dry straight out of the bottle.
For filling my tyres at a garage I tend to blow the airline out a bit to clear out any standing water.
leorest said:
I have used both N2 and dry compressed air for cooling/keeping clean high power laser optics in industry and the only differences noted were that due to poor maintenance you always get water, oil, crap in compressed air whereas N2 comes clean and dry straight out of the bottle.
By the very nature of the way N2 is separated from air, it is going to be dry. For any of the separation technques the air has to be dried before the N2 is separated and if you're getting your N2 out of a bottle it will probably have ben produced cryogenically - the air is definitley dry otherwise it'll freeze in the heat exchangers.
Your average garage forecourt does not have the means to dry the air as thoroughly even if it kept the equipment maintained.
But I'm not convinced thta is the reason for N2 filling, I think it's more likely due to the lower permeation rate which keeps the pressures more stable and the benefit here on raod tyres is dubious. They use it for racing tyres which generate considerably more energy and are more sensitive to pressure changes.
profstoff said:
I read the article in Sprint and thought "that's not quite right" but neither James nor Ash have got it quite right
to be continued
black circles.com said:
Why fill my tyres with Nitrogen?
Why would you want to do this? The benefits of Nitrogen filling are as follows:
Improved comfort of ride
Improved safety
Increased fuel savings
Improved life of tyre
Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).
The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.
Why would you want to do this? The benefits of Nitrogen filling are as follows:
Improved comfort of ride
Improved safety
Increased fuel savings
Improved life of tyre
Nitrogen has long been the accepted gas medium for filling aircraft tyres, racing tyres and heavy mining and construction vehicle tyres. Nitrogen is used for safety reasons and to ensure that tyres are always at a constant pressure. Compressed air, the traditional medium for inflating car tyres, contains both oxygen (21%) and nitrogen (78%).
The rubber tyre is like a membrane, through which oxygen permeates three times faster than the nitrogen. The result is that the oxygen slowly leaks out through the rubber walls, and the under-inflation leads to higher tyre wear with a consequent decrease in safety and comfort, and higher fuel costs.
to be continued
Edited by profstoff on Tuesday 11th July 07:19
I thought someone from the Industrial Gas industry would pop his head up at some point
It's all hot air to me anyway..
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