Nitrogen in Tyres

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effbee584

effbee584

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Well my new thread sure started something, I'll go with the 'nitrogen is better' brigade.
 

flango

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I'm not been funny and don't want to start an argument but tyresave have got it well wrong. The Nitrogen used for tyre inflation is OFN Oxygen Free Nitrogen it contains NO, NIL, None Oxygen. Tyres are inflated from high pressure cylinders of pure OFN, I do not know anyone who uses separated Nitrogen to inflate tyres, in this case I would totally agree there is no benefit in it whatsoever. If you are considering Nitrogen fill then it has to be OFN sometimes called technical grade nitrogen from a high pressure grey and black cylinder or I totally agree a complete waste of money.
 

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I can assure you that after 32 years in professional motorsport it's not.£1.50 a pop is well worth it more stable pressure for longer and hence improved mpg
Rough calculation but when you put a tyre on a rim and before you pressurise it (using nitrogen) it contains air. Atmospheric pressure is ~ 15 psi and tyre pressure of 30 psi means doubling the pressure means doubling the (uncompressed) volume of gas in the tyre. So you end up with a 50/50 split of air and nitrogen - or around 90% nitrogen instead of 80% had you just filled it with air.

As it's so critical in motorsport do you take steps to 'blow out' the air in the unpressurised tyre and if so how?

Serious question by the way - I suspect for the majority of drivers it's of little consequence but on a race track where 100ths of a second can split cars I can see why you'd want to do it!
 

jefrs

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Nitrogen does not accept moisture like normal air does so it keeps the pressures more constant.

Thats all.

You will notice your pressure remain very stable when checking them week after week.
Er, yes it does but the stuff you get out of the compressed N2 bottle is very low on water vapour. It is slightly soluble in water, to ~20mg/litre, it will therefore absorb some water. So moisture is typically <2vpm.

It's the water content that is the real problem, not the gasses - nitrogen, oxygen, carbon-dioxide, plus traces of other stuff.

Actually bottled nitrogen is ridiculously cheap. Made by fractional distillation of liquefied air. It's the outlay on the equipment that is expensive.

Haz sheet
http://www.bocsds.com/uk/sds/industrial/Nitrogen_oxygen_free.pdf
I observe that all fire extinguishers may be used.
Why? - it's not flammable!
 

flango

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Rough calculation but when you put a tyre on a rim and before you pressurise it (using nitrogen) it contains air. Atmospheric pressure is ~ 15 psi and tyre pressure of 30 psi means doubling the pressure means doubling the (uncompressed) volume of gas in the tyre. So you end up with a 50/50 split of air and nitrogen - or around 90% nitrogen instead of 80% had you just filled it with air.

As it's so critical in motorsport do you take steps to 'blow out' the air in the unpressurised tyre and if so how?

Serious question by the way - I suspect for the majority of drivers it's of little consequence but on a race track where 100ths of a second can split cars I can see why you'd want to do it!
When you fit a new tyre or have air replaced by nitrogen in a tyre, the correct way is to suck out the air then refill with nitrogen rather than blow the air out. The kit that does this is incredibly expensive and not many people have it usually professional motorsport outfits or high end tyre fiters. Once you have got the nitrogen fill it's only a matter of topping up and checking from an OFN bottle.

I accept you can never remove all the air but suspect you can have < 1% oxygen in a nitrogen fill which will make a difference
 

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In a former life I had responsibility for a large commercial fleet and, intrigued by the arguments for nitrogen, asked our engineers to look at the pros and cons of using it in our vehicles. In the end it was a no - in a fleet where tyre pressures are checked daily the 'maintained pressure' argument carried little weight.

For me a pressure check is akin to an annual service (OK maybe a couple or three times a year) but even so I see little degradation in pressure.
 

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I just check the pressure of my tires weekly and keep them at around 40psi (slightly over inflated). Hardens the ride but improves my fuel economy. Stable tire pressures can be achieved with little more than a foot pump and a bit of effort.
 

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Rough calculation but when you put a tyre on a rim and before you pressurise it (using nitrogen) it contains air. Atmospheric pressure is ~ 15 psi and tyre pressure of 30 psi means doubling the pressure means doubling the (uncompressed) volume of gas in the tyre. So you end up with a 50/50 split of air and nitrogen - or around 90% nitrogen instead of 80% had you just filled it with air.

As it's so critical in motorsport do you take steps to 'blow out' the air in the unpressurised tyre and if so how?

Serious question by the way - I suspect for the majority of drivers it's of little consequence but on a race track where 100ths of a second can split cars I can see why you'd want to do it!
The 30 psi you refer to is actually 30 psig, i.e. 30 psi above atmospheric which makes it a 33/66 mix of air and nitrogen. Psig is pressure per square inch gauge meaning the gauge shows zero at atmospheric. A psiA gauge measures from zero pressure so is rarely found in general use.
 

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When you fit a new tyre or have air replaced by nitrogen in a tyre, the correct way is to suck out the air then refill with nitrogen rather than blow the air out.
I don't get that at all. Surely with a normal tubeless road tyre any kind of vacuum inside would cause it to pull away from the rim ... there would be no seal :dk:
 

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When you fit a new tyre or have air replaced by nitrogen in a tyre, the correct way is to suck out the air then refill with nitrogen rather than blow the air out.

I accept you can never remove all the air but suspect you can have < 1% oxygen in a nitrogen fill which will make a difference
The procedure for making a vessel (or tyre) inert is to pressure up to say 3 bar with nitrogen, depressure and repeat about three times. Each time reduces the oxygen content by 75%. Increase the pressures or the number of inflations as required.

No need for any special equipment as nitrogen is usually the cheapest option.
 

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When you fit a new tyre or have air replaced by nitrogen in a tyre, the correct way is to suck out the air then refill with nitrogen rather than blow the air out. The kit that does this is incredibly expensive and not many people have it usually professional motorsport outfits or high end tyre fiters. Once you have got the nitrogen fill it's only a matter of topping up and checking from an OFN bottle.

I accept you can never remove all the air but suspect you can have < 1% oxygen in a nitrogen fill which will make a difference
I don't get that at all. Surely with a normal tubeless road tyre any kind of vacuum inside would cause it to pull away from the rim ... there would be no seal :dk:
The procedure for making a vessel (or tyre) inert is to pressure up to say 3 bar with nitrogen, depressure and repeat about three times. Each time reduces the oxygen content by 75%. Increase the pressures or the number of inflations as required.

No need for any special equipment as nitrogen is usually the cheapest option.
As Bill suggests sucking the air out of the tyre will surely distort the tyre and break the seal introducing more ambient air, and doing it in one hit would pretty much crush the tyre.

The only alternative is repeated cycles of deflation, but I can't help but think that even three cycles would still contain sufficient traces of non-nitrogen gasses?

:dk:

I guess in motorsport, the smallest gains are pursued, and so repeated cycles is worth it, and unless the tyres are removed from the rims, the concentration of Nitrogen will continue to improve with top ups.

As a side...

My father-in-law even inflates his caravan tyres with nitrogen, not because of the benefits, but because it's easier than his foot pump, and quiter than his compressor. :thumb:

My caravan has lost less than PSI in two seasons, ie 18 month, without topping up, and with checking perhaps 10 times. I know because I started 2010 0.5 PSI over the recommended, and the last check was 0.5 PSI under. That's pretty stable, and I can't imagine Swift sent it out of the factory with Nitrogen in the tyres!!
 

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I suspect the nitrogen fill argument is another "it's used in Motorsport so must be better" fad.

As mentioned in the link, they use it in motorsport because it's convenient and inert, not because it has special qualities.

My tyres were filled with nitrogen, but I don't see any real benefit, nor would it influence me to use a particular tyre fitters.
 

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I don't get that at all. Surely with a normal tubeless road tyre any kind of vacuum inside would cause it to pull away from the rim ... there would be no seal :dk:
Nope as I said you can't suck all the air out, so the machine sucks it out to a given limit so the tyre doesn'e distort or pull away from the rim and then automatically fills with nitrogen, repeated cylce filling with nitrogen I guess is just the cheap way of doing it but probably has the same effect.

I can only speak for kit I have seen used in motorsport
 

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Nope as I said you can't suck all the air out, so the machine sucks it out to a given limit so the tyre doesn'e distort or pull away from the rim and then automatically fills with nitrogen, repeated cylce filling with nitrogen I guess is just the cheap way of doing it but probably has the same effect.

I can only speak for kit I have seen used in motorsport
Is this the type of kit you're referring to Ian?
Uniflate - Nitrogen Tyre Inflation - Nitrogen News
 

flango

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Is this the type of kit you're referring to Ian?
Uniflate - Nitrogen Tyre Inflation - Nitrogen News
I don't think so it's not clear from the spec sheet but I think this may be one of the units fed by compressed air :dk: to produce nitrogen fill, the units I have seen are fed on bottled OFN and I know for sure the units used by the Ferrari F1 team are from Snap On as are all the teams tyre changing and balancing machines, as we have exactly the same. But we don't have initial nitrogen fill we use a local company for that due to the excessive cost of the equipment.
 

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I don't think so it's not clear from the spec sheet but I think this may be one of the units fed by compressed air :dk: to produce nitrogen fill, the units I have seen are fed on bottled OFN and I know for sure the units used by the Ferrari F1 team are from Snap On as are all the teams tyre changing and balancing machines, as we have exactly the same. But we don't have initial nitrogen fill we use a local company for that due to the excessive cost of the equipment.
The reason I thought it was is in their claim regarding F1, see quote:-


Welcome to Uniflate.com the home of
Nitrogen Tyre Inflation.

Uniflate has been established since 1992 as a result of a research programme into an onsite nitrogen production facility to replace the high pressure nitrogen bottles that were being used in Formula 1.

Since its successful launch Uniflate continue to be the sole supplier to the Formula 1 industry but also now provide systems to garages and fast fit tyre centres around the UK as more commercial vehicles and LGV’s are now fitted with nitrogen tyres.
 

Dieselman

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Is this the type of kit you're referring to Ian?
Uniflate - Nitrogen Tyre Inflation - Nitrogen News
I like Clarksons quote on the Nissan GTr having nitrogen filled tyres and the general attention to detail...

The attention to detail has been extraordinary. For instance, the GT-R’s tyres are filled with nitrogen because ordinary air expands and contracts too much. And each gearbox is specifically mated to each handmade engine”

Does that mean "bolted together"..?:rolleyes:
 

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