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Nitrogen in Runflat tyres
- Thread starter AshG108
- Start date
AshG108
///Member
hi guys, the tyres are wearing on the outsides more than the centres, i was advised to run the tyres slightly higher than the normal to get the centres to wear out a bit more to bring it to even wear all over the tyre.
but what amazes me is my car went in to BMW, they checked the tyre pressures and said it was 2.2bar front, 2.4bar rear but the same night, i went to a garage and it was 1.5bar all around??? now what i am amazed at is either all tyres are losing air very quickly(which i am quite suprised that it will happen) or rather the dealership inflated it incorrectly and reset my TPM cause my TPM never came on to say it dropped to that level and i had previously check the pressure and always maintained it to the levels on the door sill.
i have the tyre pressure gauge from the Mobility Kit, havent used it before but will use it to check the tyres now and see how it goes.
but what amazes me is my car went in to BMW, they checked the tyre pressures and said it was 2.2bar front, 2.4bar rear but the same night, i went to a garage and it was 1.5bar all around??? now what i am amazed at is either all tyres are losing air very quickly(which i am quite suprised that it will happen) or rather the dealership inflated it incorrectly and reset my TPM cause my TPM never came on to say it dropped to that level and i had previously check the pressure and always maintained it to the levels on the door sill.
i have the tyre pressure gauge from the Mobility Kit, havent used it before but will use it to check the tyres now and see how it goes.
Philip Foglar
///Member
Okay, I am a believer in Nitrogen for one specific reason - there is virtually no chance of having moisture (water) getting in. True, air is mostly made up of Nitrogen, but as in the above, there is often a lot of moisture in the air and especially from a normal air compressor. Personally I let them put Nitrogen in (yes, costs a little, but once off) and then whenever necessary I simply top up with my air compressor. So technically defeating the objective, but my logic is - Oxygen is less dense than Nitrogen, so escapes quicker from the tyre since rubber is porous. So after a while assuming you keep topping up with pure Nitrogen any remaining Oxygen (from when the tyre was fitted) will eventually work its way out.
I think the main idea is to maximise the amount of Nitrogen and minimise the amount of moisture in the tyre - this allows for more consistent pressure and also importantly lower operating temperatures (tyres don't get as hot and tyre pressures don't fluctuate as much from temperature change).
But important, especially with RFT's - make sure you have an accurate and trustworthy pressure gauge and monitor the tyres pressures on a regular basis. You aren't going to see a low pressure RFT tyre as easily as a non-RFT tyre!!
I think the main idea is to maximise the amount of Nitrogen and minimise the amount of moisture in the tyre - this allows for more consistent pressure and also importantly lower operating temperatures (tyres don't get as hot and tyre pressures don't fluctuate as much from temperature change).
But important, especially with RFT's - make sure you have an accurate and trustworthy pressure gauge and monitor the tyres pressures on a regular basis. You aren't going to see a low pressure RFT tyre as easily as a non-RFT tyre!!
i did not think about the moisture... i always do my own tire pressure because it stays more constant when i do...
my reasoning is that when i check my tire pressure and it is right i dont put more air in... so the air that is in there has very low O2 because the O2 defuses threw... when the fuel guy does it he puts on a big 'show' of putting in more air and i dont think most of them even bother trying to get the right pressure...
so topping up the little bit that defuses out eventually leaves you with almost no O2...
this does not help with the moisture thou which will affect your pressure when the tire is warm...
i normally see a 0.3 increase in pressure with warm tires... would be interesting to see how it compares to nitrogen...
my reasoning is that when i check my tire pressure and it is right i dont put more air in... so the air that is in there has very low O2 because the O2 defuses threw... when the fuel guy does it he puts on a big 'show' of putting in more air and i dont think most of them even bother trying to get the right pressure...
so topping up the little bit that defuses out eventually leaves you with almost no O2...
this does not help with the moisture thou which will affect your pressure when the tire is warm...
i normally see a 0.3 increase in pressure with warm tires... would be interesting to see how it compares to nitrogen...
Nitrogen wont damage your tires, but im not sure its worth it...
Skwinty
New member
I have looked into this and came to the following conclusion.
Aircraft and race cars will benefit from reduced operating temperatures but not so much road cars.
See link from Scientific American
http://www.scientificamerican.com/article.cfm?id=nitrogen-filled-tires-fuel-efficiency
Aircraft and race cars will benefit from reduced operating temperatures but not so much road cars.
See link from Scientific American
http://www.scientificamerican.com/article.cfm?id=nitrogen-filled-tires-fuel-efficiency
im with Skwinty on this one, but i would like to know how Philip Foglars pressure differs from hot/cold compared to mine :rollsmile:
Philip Foglar
///Member
They use normal air to "seat" the tyre onto the rim and then allow the tyre to fully deflate again. At this point they fit the valve and then fill will Nitrogen, so technically there is still "ambient" air in the tyre under normal atmospheric pressure before the tyre is pressurised with Nitrogen. For the tyre to be 100% filled with Nitrogen you can think they would have to fit the tyre in a Nitrogen filled enclosure and then pressurise it, or use a vacuum to remove the excess air which is probably more risky and difficult, not to mention most likely to cause damage to the tyre...
Can't do any harm to put Nitrogen in, and cheap at most places - apparently Total filling stations top up with Nitrogen for free!!! :idea:
Have never actually checked that, would be interesting to see what the differences are. And since my wheels were repaired earlier this year at Magworkshop, for the moment it still has normal air inside rather than Nitrogen (haven't got around to having TWT replace the Nitrogen) - so can do a before and after test for this in due course!
Can't do any harm to put Nitrogen in, and cheap at most places - apparently Total filling stations top up with Nitrogen for free!!! :idea:
moranor said:
Have never actually checked that, would be interesting to see what the differences are. And since my wheels were repaired earlier this year at Magworkshop, for the moment it still has normal air inside rather than Nitrogen (haven't got around to having TWT replace the Nitrogen) - so can do a before and after test for this in due course!
WyKiD
Active member
I have tried nitrogen in my tyres in the past and did not notice any difference in the wear or making the tyres last any longer. For the issue with your tyres wearing on the outside very unlikely that nitrogen will be of any help. Slightly higher pressure might help even out the wear due to the tyre running more on the middle of the tyre than the edges. Also ensure that alignment is correct esp. cambers and toe in settings if avail. on your model. If your cornering speeds is excessively high this would also lead to the edges of your tyres wearing....
XMAX
///Member
I also dont believe in nitrogen. kind of a gimmick.
I also wonder about the temperature of tyres vs the pressure they indicate.
also, the time of day that the tyres are filled. does this make a difference like it does when filling petrol (where one should fill when its very cold, like early morning, or late evening, due to the density of the fuel at these times of day)?
I also wonder about the temperature of tyres vs the pressure they indicate.
also, the time of day that the tyres are filled. does this make a difference like it does when filling petrol (where one should fill when its very cold, like early morning, or late evening, due to the density of the fuel at these times of day)?
Philip Foglar if you do check please post what you find
Philip Foglar
///Member
moranor said:Philip Foglar if you do check please post what you find
I shall! :=):
