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Old 28 September 2013, 10:49   #11
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ATS offered to fill my new tyres with nitrogen, they said they would maintain they're pressure, the bloke then said I could come in once a month to get them topped up for free, I said if they maintained pressure why would I need to, he looked stumped.
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Old 28 September 2013, 11:54   #12
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Air has water vapour in it. This expands a lot with heat and contracts with cold. The Nitrogen will be dry and will maintin a more constant pressure regardless of the temperature.
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Old 28 September 2013, 12:25   #13
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Except Helium is He: Hydrogen exists as H2
Aye my bad, typo
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Old 28 September 2013, 12:26   #14
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Air has water vapour in it. This expands a lot with heat and contracts with cold. The Nitrogen will be dry and will maintin a more constant pressure regardless of the temperature.
Air can be dried, diving air is VERY dry.
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Old 28 September 2013, 12:59   #15
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Oh the huge manatee, the huge manatee...
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Old 28 September 2013, 15:14   #16
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Air has water vapour in it. This expands a lot with heat and contracts with cold. The Nitrogen will be dry and will maintin a more constant pressure regardless of the temperature.
Are you sure about this? My understanding is that water volume is not significantly affected by temperature. If it was our central heating systems would explode, and kettles would overflow?
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Old 28 September 2013, 15:48   #17
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jeeez... thats why there is a max fill mark on a kettle, and things such as 'expansion' (note that name) tanks on car coolant systems!
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Old 28 September 2013, 15:59   #18
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Air is 78% nitrogen, and O2 does cause degradation to many rubber and plastic items (Albeit mostly in higher concentrations of O2). If it is free, why not fill with nitrogen? If it requires doing any kind of extra work or driving, forget about it.

I have a 5,000 psi compressor that produces very dry air @32% O2, and the only time I would ever consider using it in my tubes, is in an emergency while out on the water. Otherwise I just use a hand pump.
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Old 28 September 2013, 16:01   #19
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Air has water vapour in it. .
yes but not a lot of it! Air is according to my 1980-something O level notes circa 79% nitrogen, 19% oxygen & bits of other stuff inc. some CO2. The other stuff in will depend on local conditions.

However if anything there must be more CO2 in the air now - as we now have global warming which we didn't back ten.

Then again I never was very good at science

Can't see it would make a significant difference, but I'm no scientist.
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Old 28 September 2013, 16:13   #20
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Here you go, study this...... Thermal expansion - Wikipedia, the free encyclopedia

All the info is there and makes a more interesting Saturday night than watching the X Factor.
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