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Discussion Starter · #1 ·
My service center has been advertising nitrogen filled tires for some time now. Does anyone here have any experience w/ nitrogen filled tires and pros/cons?

The main theme they say is that it maintains tire pressure longer, including in extreme temperatures (hot and cold), and that b/c nitrogen is "dry" as compared to regular air where it won't slowly rot the inside of your tires out from condensation, etc.

any truth to this, does it matter and make that much of a difference?
 

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pure dealer profit. save the cash.

air is 78% nitrogen.
 

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Discussion Starter · #3 ·

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Already had it in the tires when I picked it up. Hadn't noticed any problems, it is advertised to help keep any condensation from forming on the inside of the rims. Don't know that I'd run out and replace regular air for it.
 

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Nitrogen is an inert gas....very stable, what it does for tires is: The pressure does not fluctuate much at all from hot to cold, It is very stable and does not promote tire oxidation, internally...many owners of restored cars fill their tires with it for long term storage....10 years... Does anybody who drives their car all the time need it ???NO...a waste of $$$$$$$...It DOES NOT help to keep your tires inflated any longer than regular air does, on a daily basis.
 

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Nitrogen is an inert gas....very stable, what it does for tires is: The pressure does not fluctuate much at all from hot to cold, It is very stable and does not promote tire oxidation, internally...many owners of restored cars fill their tires with it for long term storage....10 years... Does anybody who drives their car all the time need it ???NO...a waste of $$$$$$$...It DOES NOT help to keep your tires inflated any longer than regular air does, on a daily basis.
That's a misconception.

The tire pressure DOES fluctuate from hot to cold with pure nitrogen, and it's much more than "not much at all." The advertisement gimmick is that the amount pure nitrogen fluctuates is less than that of air, but air is nearly 4/5's nitrogen as it is...

To put it in perspective, Nitrogen is an ideal gas. For ideal gasses, PV=nRT. P = Pressure in Pascals, V = Volume in cubic meters, n = number of moles, R = 8.314 (gas constant), and T is temperature in Kelvin.

To compare an ideal gas pressure at two different temperatures, the V, n, and R cancel out and leave P/T = P/T.

80* F = 26.7* C = 299.81 Kelvin

38 PSI = 262000 Pascals (Pa).

So lets say the temperature falls to 40*F on a cold night. That's 4.4* C = 277.6 Kelvin.

Punch that into the P/T = P/T equation and you your new pressure is 242590 Pa, which is roughly 35 PSI.
 
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Great advice. Basically, it's not needed and is a waste of money. Just a plow by service shops to charge more for something you don't need.
 

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is it that expensive ?? i filled my tires in nitrogen for a cheap price (15 dollars only) .
 

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The simple answer is its probably not worth it.


The complete answer is a little more complicated.

The pressure fluctuation benefit is because the nitrogen is highly compressed (to ~3000 psi) and is therefore very, very dry.
Most garages 'shop air' is compressed to ~125-200 psi and contains much more moisture from the humidity in the air.
At temperature, the vapor pressure of the water raises the tire pressure more than with totally dry air.
For this reason, I keep a filled SCUBA tank around for filling my tires.
Its air, not nitrogen, but it is as dry as the nitrogen in bottles.
and it is very handy on track days.

Pure nitrogen due to the lack of oxidation, may be slightly beneficial to tire life.
I suspect with modern tires, its not an issue.

.
 

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The air we breathe is approx 78% nitrogen and 21% oxygen. The nitrogen that tire shops sell is simply air with the oxygen removed.
A nitrogen air bubble is about 3 times the size of an oyygen air bubble so in cold temperatures it's harder for the nitrogen to escape from the tire.

I've had nitrogen in my tires for the past year and haven't had my TPMS light go on once. When I used regular air, the light would come on weekly.
 

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Discussion Starter · #12 · (Edited)
thanks for all the responses!

i'll keep my tires w/ regular air then.
 

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We used to run nitrogen in the go karts and the the PSI could jump as much as 50% with just air. With Notrogen they never went up if so very little at all. So yeah it does work and if you are going to be racing the car I would do it.
 

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Race teams use nitrogen because the pressure fluctuates much less when the tires get up to racing temperatures. This allows them to get the "hot" pressures more precise. With air, we use tire pressure measurements immediately after coming off track to see how high the pressures are, and then adjust accordingly. Depending on the tire, it is common to see cold to hot fluctuations of 8 psi or more, meaning there is some guesswork/careful estimating involved in setting the cold pressures in an effort to achieve the desired hot pressures. Even with air, though, we can routinely nail hot pressures within a psi of the desired setting. Pro teams and pro drivers can tell differences between even minute tire pressure settings, so they go for the nitrogen. For street use, it's a complete waste.
 

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Discussion Starter · #16 ·
For street use, it's a complete waste.
after all the feedback, these are my thoughts exactly. I do not intend to race my M5
 

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is it that expensive ?? i filled my tires in nitrogen for a cheap price (15 dollars only) .
lol...when air is free that is real expensive!!!!!!! Then again I am known for being a cheap *** haha ouich
 
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