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Air or Nitrogen

DarthUrsula

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#1
Hello all,

Wanted to get some advice. My tires are currently nitrogen filled but there really isn't anyone around me that can fill nitrogen. Should I just go with air?
 


TyphoonFiST

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#3
Hello all,

Wanted to get some advice. My tires are currently nitrogen filled but there really isn't anyone around me that can fill nitrogen. Should I just go with air?
That is a complete Snake oil sale* hopefully you didnt buy into it and it was FREE* You can run air its just fine.....Nitrogen is just a Fad. It gives minimal advantages
 


D1JL

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#4
I agree, just use air.
Nitrogen is best for track days as it reduces tire temps.

Too bad there is no one trying to use Helium.
I wonder if that would even work?
 


TyphoonFiST

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#5
I agree, just use air.
Nitrogen is best for track days as it reduces tire temps.

Too bad there is no one trying to use Helium.
I wonder if that would even work?
Then we could really see pigs fly!
 


OP
DarthUrsula

DarthUrsula

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Thread Starter #9
Thank you all. I decided to just top it off with air until I can fully get them drained then filled with air
 


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St. Paul
#10
Thank you all. I decided to just top it off with air until I can fully get them drained then filled with air
I don't think I would worry about getting them "drained" at all, just keep topping with air.
"air" is ~75% nitrogen anyway, it will all come out in the wash in the end and as others have stated, it doesn't make a difference.
 


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#11
I agree, just use air.
Nitrogen is best for track days as it reduces tire temps.

Too bad there is no one trying to use Helium.
I wonder if that would even work?
I would thing that your wheel assemblies would be "slightly" lighter, though it probably only a miniscule amount.
a reference article about the weight of air in a tire - so you only have ~30g of air in the tire, if hydrogen molecules are 1/5 the density, then you would have 6g of helium, saving 24g/wheel assembly. and the entire wheel assembly on a fiesta weighs ~20,411g... probably not worth the effort on weight alone unless it was top tier racing and even then it may not be worth the effort.

With the helium molecule being smaller it is probably slightly harder to contain under pressure, I would think this will lead to needing to fill the tires even more frequently.

I guess I will site an article that tries to be scientific about it, they also try to make a point about nitrogen in tires... tho, I still don't think it's worth filling with Nitrogen.

(there are links in here, they dont show up in night mode well so I made them bold and italics)
 


Last edited:

SteveS

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#12
The only point of nitrogen is that it doesn't contain moisture and won't oxidize the tires. Racers in F1 and Indycar may use nitrogen because then there is no variability in the moisture and therefore no variability in thermal expansion and pressure increase.

On a daily driver or a track car or a car with 200TW tires, which is likely with a Fiesta ST, the tires aren't going to be on the car long enough for oxidation from the filled air to happen. And you aren't going to have any problem from the use of air rather than nitrogen, and there's no need to "flush" the nitrogen. (If you are switching TO nitrogen, you do have to numerous empty/fill cycles to achieve an almost all nitrogen fill).
 


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#13
I would just top off with air and leave it be, regular air is around 79% Nitrogen. To really fill a tire with all nitrogen you would have to draw a vacuum first and then fill with Nitrogen. That would take some fancy manchinery and I would think the headache of breaking the bead/seal of the tire is not worth it for the tech even so. Just topping off wouldn't add much moisture if you do it on a low humidity day.
 


Dialcaliper

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#15
I agree, just use air.
Nitrogen is best for track days as it reduces tire temps.

Too bad there is no one trying to use Helium.
I wonder if that would even work?
Having worked with Helium, it is much more difficult to contain, being a very small, non-reactive atom, is even harder than containing hydrogen. With something like a rubber car tire with a simple low pressure bead seal, your tire will likely be flat in a matter of days.

Thereā€™s a reason that vacuum chambers and many other systems that are designed to be sealed really really well use whatā€™s called ā€œhelium leak testingā€ to verify seal integrity, which is basically a leak down test where you fill the system with helium gas and measure how slowly the pressure drops.

The reason to use nitrogen in a tire is that it has little to no water vapor and behaves more like an ideal gas than the humid air coming out of a compressor (which can only be dried so much with a dessicant cartridge), so the pressure will change less with temperature. Good for race cars where tire temperatures get pretty toasty because you can run several PSI lower hot pressures for that tiny sliver of extra grip without having your tires go flat when they get cold.

Also, nitrogen gas is basically a waste product of the ā€œair productsā€ industry that produces stuff like bottled oxygen, liquid nitrogen, welding gasses, etc etc, so itā€™s dirt cheap. For most tire shops, itā€™s cheaper to have nitrogen bottles filled to air up tires than it is to invest in a proper desiccant cartidge setup for their shop air system, or separate small compressors with driers just for filling tires, both of which can get pretty spendy. And the cheap advertising to most consumers that think it must be a good thing.

For a street car the benefit is minimal at best, but if youā€™re using your own compressor at home, a very small dessicant air drier can be had for pretty cheap.

That said, Nitrogen is really cheap too - itā€™s just the upfront cost of bottle rental, regulator and the extra hoses and fittings that will cost you.
 


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#16
I get what everyone is saying about just using air ā€¦.. in the past, with a tire that came with nitrogen from the dealer on a street car, I just topped off with air.

But Iā€™ll say this ā€¦. On my track dedicated FiST, front tire pressure with air gets CRAZY; Iā€™ll go from 26lbs cold to mid-40s hot on a warm day during a 25 min session. I have wondered whether a true nitrogen fill would be in my best interests in that scenario.
 


Dialcaliper

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#17
I get what everyone is saying about just using air ā€¦.. in the past, with a tire that came with nitrogen from the dealer on a street car, I just topped off with air.

But Iā€™ll say this ā€¦. On my track dedicated FiST, front tire pressure with air gets CRAZY; Iā€™ll go from 26lbs cold to mid-40s hot on a warm day during a 25 min session. I have wondered whether a true nitrogen fill would be in my best interests in that scenario.
Especially if you live somewhere very humid and donā€™t use a dryer cartridge after your compressor, it might be worthwhile. What happens is that the compressor makes the air hot during the compression process, which allows it to pick up more moisture, which once it cools pools up in the bottom of the compressor tank, so the air is basically 100% humidity and warm. When the really humid pressurized air gets in your tire and cools down more below the dewpoint, you basically get excess moisture forming tiny droplets inside your tire, which greatly reduces the volume of the water fraction of the air in the tire.

When your tire heats up on the track, the warmer air inside can hold more moisture, that water evaporates and expands from dense liquid into a gas, increasing the pressure a lot more than just heating a dry ideal gas would.
 


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