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Nitrogen in tires?

1K views 5 replies 6 participants last post by  VMRWheels 
#1 ·
I have heard this improves steering since normal o2 expands and condenses. Is this true?
 
#4 ·
Only advantage of nitrogen ( N2 further) is that , by way they make it, there is no water in it. Water ( H2O) can give rust to metal rimms, and expands strange with the temperature , because it chanches from gas to liquid at sertain temperatures and pressures. Also liquid water can dissolve the O2 ( Oxigen) and N2 les of more.
When you would have dry air ( 80% N2 and 20% O2 roughly) it will expand exactly the same with temperature rise.
N2 holds more energy , so in short time can give less temperature rise and so pressure-rising, but in the long term 100% N2( if you can manage to fill it) in the tire gives the same temperature in the tire as dry air.

But dont think that you have 100% N2, the empty tire also holds some 20% O2 at 1 bar outside pressure. Filling it to 3 bar ( 42 psi) overpressure makes 4 bar real pressure in the tire with 5% O2.
If you manage, by filling with N2 , letting out all the pressure , and filling again with N2, to bring this O2 back to 1% , in a year or so the %O2 is 5% again.
the O2 goes from outside to inside , against the high pressure.
Called the law of Pascal I think, 20% O2 at 1 bar means partial pressure O2 =0,2 bar.
The 3 bar filled with 100% N2 tire of the example here, the Partial pressure ( further Pp) O2 still is 0,2 bar . Outside tire also 0,2 bar O2 so the O2 is yust as fast going in then out so Pp O2 stays the same. Only N2 is leaking out then, but slower because N2 difuses 5 times as slow trough the rubber then O2.
Filling to 1% O2 at 3 bar means 4*0,01=0,04 bar Pp O2 so outside still 0,2 , means that O2 is faster going in then out the tire so the loss of N2 is partly compensated by the filling of O2.

To make the story more complicated, water ( H2O ) when it is a gas reacts to the same Pp laws of pascal, so if you have filled with dry air, in a jear or so there will be water inside the tire.

could even be that by an interaction of gas and liquid water trough temperature and humidity chanches , it is possible that the tire is collecting even more water or yust looses it in time. that is what I am trying to figure out at the moment.
 
#5 ·
Normal air is already almost 80% nitrogen. Shops don't have the ability to fill consumer tires with 100% nitrogen. You are paying for a marginal increase in nitrogen and helping your local shop make some extra money.

The difference in air permeation is very little, roughly 0.5psi per month. A tire with standard air that is normally maintained with the proper air pressure will perform exactly like a tire with a pure nitrogen fill. If you can get a pure nitrogen fill for free, there is no harm in doing so but very little (if any) benefit from it.
 
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