any one know of a dealer who offers nitrogen tyre inflation in the west midlands.
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As air is 80% N,why do you want it?.
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If the oxygen and water vapour have permeated through your tyres then you should be left with nitrogen in the tyres already. Each time you top up the pressure you have less water vapour and oxygen in until eventually you are left with just nitrogen. Alternatively if compressed air was, say, 70% nitrogen then overinflate your tyres by 50% and wait for all the oxygen and water vapour to permeate out, then adjust the pressure down to the correct level. If this sounds a bit pointless then so does filling your tyres with nitrogen, why not fill them with helium to reduce the unsprung weight, but then that's another topic. ;-)
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How do you get rid of all the air that is in the tyres already (not under pressure, just the large volume that the tyre holds)?
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How do you get rid of all the air that is in the tyres already (not under pressure, just the large volume that the tyre holds)?
Fit tubes, evacuate them first?
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When you inflate a tyre to 30PIS, you are trebling the amount of air in the tyre from the amount that was in at normal atmospheric pressure, as one atmosphere = 15PIS. So unless you did evacuate the tyre before inflating with N, it will still have 1/3rd of the none Nitrogen gases, so why bother. If they do evacuate the tyre, it would break the bead and cause other problems with seating/leaking.
It's another case of emporer's new clothes.
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Have a look at www.uniflate.com
principal benefit is that it is the o2 molecules that leak through the tyre causing pressure to drop.
In theory, if you keep toppping your tyres up - you will be left with a Nitrogen rich gas mix in your tyres - the company themselves state that their process carries out the same and what happens naturally in car tyres over a period of months.
I have seen a car with tyres that were inflated using nitrogen (very common in europe) and the tyres have not lose ANY pressure over 2 years.
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The paradox is that the faster the tyre leaks oxygen, the quicker it would become filled with nitrogen alone. If you could make a tyre that lost oxygen so quickly you could hear it hissing out, but kept all its nitrogen, it would become nitrogen-rich during its first inflation.
It seems a lot of bother for nothing though.
Or if tyres were filled with butane it would be much easier to spot leaks, with a lighter.
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Pop down to Birmingham Airport - their technical department should be able to do it for you. Just disguise your car as a Boeing 737!!
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Sorry ST atmospheric pressure is 14.7psi at sea level.correct me if wrong.I think one point is being missed here with N filled tyres.as it is an innert gas is used to help prevent cars from.on tyre`s that are on fire ie after an accident.prevent them from making the fire worse than it is which happens after the tyre explodes through heat.the N factor stops a burst of flame that could cause a lot more damage than it would if normal compressed air used.so I dont think a waste of time.safety I think is more the issue here?
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It isn't the tyre pressure that's relevant, but the partial pressure of the oxygen.
Some dead geezer's law (Avagadro, Dalton?) states that the total pressure of a gas mixture is the sum of the pressures exerted by the individual components. With the tyre inflated at 30 psi with nitrogen the partial pressure of the oxygen is 0 psi. The peculiar bit is that the oxygen will leak INTO the tyre from the atmosphere, increasing it's pressure. And you still wind up with a tyre full of an oxygen/air mixture roughly approximating to air.
I've seen this happen with compressed air at 100psi, dried to minus 70degC dew-point with an absortion dryer. Moisture was permeating through the plastic (ABS) pipe walls, making the air too wet. I'm assuming the same thing will happen with oxygen.
I can see the sense of filling an expansion vessel with nitrogen; all the other pipe components, except the tank bladder, should be impermeable to oxygen. I can't see that it would have much effect with tyres. Anyone know better?
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I can't accept the fire explanation - not with a tank of petrol in there as well.
I think the nitrogen belongs to the 'keeping up with the Kevins'.
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That should have read "you still wind up with a tyre full of an oxygen/nitrogen mixture roughly approximating to air."
If it was important to keep the oxygen out of the tyres, you'd have thought the tyre makers would coat the inner wall of the tyre with an oxygen-barrier material. Some plastic pipes PEX have an oxygen barrier coating on the outside. This would reduce the rate of corrosion; as oygen in the tyre charge is used in corroding the metal on the wheel, more oxygen will permeate through the tyre wall.
The tyre makers don't do this. Perhaps they think it's of no value?
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Plane and race tyres are filled and purged, then finally charge with dry nitrogen to reduce the hot/cold pressure difference and to avoid water vapaout in the type as with an aircraft this vapour will condense out and freeze at altitude and can cause serious wheel inbalance on landing particularly noticeable on small aircraft nose wheels. It was first introduced in the aircraft industry as a safty issue to avoid any, at pressure, combustion supporting gases and the dry aspect reduces the hot/cold pressure problems. These are the two main resons F1 and others use nitrogen. I always use dry air, never use a gagage airline as they are very high in water content and when I go a tyre place to have new tyres fitted I take a dive bottle and regulator with me. That get some strange looks, but at least my rims do not corrode from the inside. Regards Peter
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