Nitrogen in tires...

[Jordo]

Originally Posted by ard

That is ABSOLUTELY FALSE.

It has been repeated and believed like an internet rumor, but is just false.

Nitrogen, like air, obeys the ideal gas law. It cannot escape this reality:

PV=nRT


End of story. But the back story:

Uncontrolled fill in tires includes moisture. Although atmospheric gases follow the ideal gas law, MOISTURE does not and will create pressure variations as it heats.

When race cars, aircraft tires are filled with 99.99% pure technical nitrogen, care is taken to eliminate any moisture. Great.

Unfortunately this "moisture free' condition is not assured with commercial 94% pure nitrogen generators. They take a truth (race cars abd jets use 99.9% pure, moisture free nitrogen) and use just the nitrogen part (94% with limited moisture control) to convince people ALL the benefits will be included.

Even sillier are the claims of safety, tire life, never needing to check air pressure, etc...

I disagree. Nitrogen is used in suspension componits for the benifit, of its ability to not change in pressure from hot to cold. (well some change, but much less then norm. compressed air) I worked in a -performance only- suspension and motor shop for a few years building Motocross suspension.
Im positive nitrogen has this property. But I will say that we do keep the bladders that we fill is 99.9% pure, moisture free nitrogen.

The bladder is the black rubber piece in the bottom right corner.



^^^ In this case the the "gas under pressure" is the nitrogen that is held in a rubber blader, to keep it from being contaiminated by any oil that may be present. As the shock heats up to over 300* that heat would drasticly change the propertys of how the shock worked, if the bladder was filled with comp. air. Filling it with nitrogen keeps the shock working consistantly from first using it and its cold, all the way up to OP temps.







(I'm bad speller... sorry)

[ard]

Originally Posted by Jordo

I disagree. Nitrogen is used in suspension componits for the benifit, of its ability to not change in pressure from hot to cold. (well some change, but much less then norm. compressed air) I worked in a -performance only- suspension and motor shop for a few years building Motocross suspension.
Im positive nitrogen has this property. But I will say that we do keep the bladders that we fill is 99.9% pure, moisture free nitrogen.

The bladder is the black rubber piece in the bottom right corner.



(I'm bad speller... sorry)

Great you have this experience.

Sorry you are not a physicist.

Nitrogen is inert, that is critical in many sealed components- it decreases corrosion and breakdown. True. But it still expands with temperature. You cannot change that.

As you point out, MOISTURE FREE is the key! You get that from a green bottle with a tag that says "99.99% certified moisture free technical grade"

Like I said, so many people have been told "nitrogen doesnt expand" that even 'professionals' will believe this! I am sure you were told this, and now you hold that as a belief. The person that told you- yes, he believes it as well. Sorry to break that bubble, but nitrogen expands.

[Jordo]

Originally Posted by ard

Great you have this experience.

Sorry you are not a physicist.

Nitrogen is inert, that is critical in many sealed components- it decreases corrosion and breakdown. True. But it still expands with temperature. You cannot change that.

As you point out, MOISTURE FREE is the key! You get that from a green bottle with a tag that says "99.99% certified moisture free technical grade"

Like I said, so many people have been told "nitrogen doesnt expand" that even 'professionals' will believe this! I am sure you were told this, and now you hold that as a belief. The person that told you- yes, he believes it as well. Sorry to break that bubble, but nitrogen expands.

Did you read my post???

Originally Posted by Jordo
I disagree. Nitrogen is used in suspension componits for the benifit, of its ability to not change in pressure from hot to cold. (well some change, but much less then norm. compressed air) I worked in a -performance only- suspension and motor shop for a few years building Motocross suspension.
Im positive nitrogen has this property. But I will say that we do keep the bladders that we fill is 99.9% pure, moisture free nitrogen.

The bladder is the black rubber piece in the bottom right corner.



(I'm bad speller... sorry)

[ard]

Originally Posted by Jordo

Did you read my post???

I did.

You cannot say "Nitrogen doesn't expand" but then say "well some, but less than "norm" compressed air."

Either the discussion is "does nitrogen obey the ideal gas law and expand just like air and all other gases or does it not?"

As a separate issue, we can discuss the impact of MOISTURE in nitrogen and the impact of moisture in air.

Moisture free air = moisture free nitrogen

Uncontrolled air< moisture free nitrogen

Uncontrolled nitrogen at tire store = uncontrolled air at tire store

So why spend $30 for nitrogen at the store? IF as JCL comments, the nitrogen is drier than the air (and there are no specs on this, no claims on this, no data on this) then the DRIER the fill the better, but otherwise no benefit.

[Harley Monster]

I have my own Nitrogen bottle and have all my rolling stock's tires filled with Nitrogen.

I have an aviation background where Nitrogen is used for a lot of things, but here are some of the reasons to use Nitrogen in the tires.

Yes, it is dry, no moisture.

It is inert so there is no oxidation of wheels,tires, valve stems or the steel belts in them.

The Nitrogen molecule is larger so tires stay inflated to proper pressure longer and is more pressure stable. This can insure the best gas and tire mileage possible. My X5's tires stay at the proper inflation pressure for over a year at a time. Compressed air leaks out of tires about 1.5 lbs a month causing a risk of running under inflated.

Nitrogen inflated tires run cooler which may add to the tire's life.

Nitorgen does not support combustion.

Topping off with compressed air is not a problem if good clean dry air is used. They say the benefits of Nitrogen are not increased in concentrations above about 96% though pure is better.

I think it is worth it, but I was already set up with the bottle and regulator.

[ard]

Have a bottle? NO PROBLEM, that is 100% N2, that is dry gas.

(However there is nothing about nitrogen that makes it cooler... zero data for that)

(Technically the N2 molecule is SMALLER than the O2 molecule.... Hmm, how can this be? everyone says otherwise... And remember, 78% of air is nitrogen...does this 78% leak out faster when it is just 'plain air'? )

Originally Posted by Harley Monster

They say the benefits of Nitrogen are not increased in concentrations above about 96% though pure is better.

.

Uh, the reason "they" say this is because their commercial nitrogen concentrators cannot get past 96%!

I commend you on using 'real' nitrogen...my issue is that consumers are being ripped off under pseudo-science.

A


PS The answer to my second comment above is this: there are tests that show the N2 molecule as minutely faster permeation times through latex rubber. (not tires) and this has been twisted by vendors in (1) stays inflated longer. (2) proper inflation increases gas mileage, (3) proper inflation is safer. Of course on the last two they leave off the "proper inflation" and say "nitrogen saves money and protects the kids"...

[TheWanderer66]

Originally Posted by ard

Have a bottle? NO PROBLEM, that is 100% N2, that is dry gas.

(However there is nothing about nitrogen that makes it cooler... zero data for that)

(Technically the N2 molecule is SMALLER than the O2 molecule.... Hmm, how can this be? everyone says otherwise... And remember, 78% of air is nitrogen...does this 78% leak out faster when it is just 'plain air'? )



Uh, the reason "they" say this is because their commercial nitrogen concentrators cannot get past 96%!

I commend you on using 'real' nitrogen...my issue is that consumers are being ripped off under pseudo-science.

A


PS The answer to my second comment above is this: there are tests that show the N2 molecule as minutely faster permeation times through latex rubber. (not tires) and this has been twisted by vendors in (1) stays inflated longer. (2) proper inflation increases gas mileage, (3) proper inflation is safer. Of course on the last two they leave off the "proper inflation" and say "nitrogen saves money and protects the kids"...

Yeah this whole N2 thing kills me. Soo many strawman arguments in favor, so many dubious claims. Oxidation of vulcanized rubber takes many years, many times longer than the typical lifespan of tire tread. Most modern compressors separate water from the compressed air, it's an easy to do and widely understood technique for paint guns, air tools, etc. Most wheels are alloys, most component parts that any moisture would come into contact with are not ferrous and so wouldn't rust anyway. If they did, heaven help your vehicle if it rained..

[Penguin]

Originally Posted by Jordo

its ability to not change in pressure from hot to cold. (well some change, but much less then norm. compressed air)

No.

"There is no significant difference in expansion and contraction characteristics of nitrogen compared to air when moisture is absent. Expansion or contraction of either gas, in relation to temperature change, occurs to a similar extent over the commonly encountered pressure and temperature ranges relevant to the discussion of tire inflation. There is no practical difference as long as the gases are dry in a fixed volume container such as a tire."

The difference is completely due to moisture content, not because it is Nitrogen.

Nitrogen is inert, and that is why it is used in shocks, e.g., does not promote corrosion or degradation/oxidation of bladder or seals.

[Danish-M]

It's a rip off since there is no second valve to extract the already existing air out of the tire.
My NT03's on my race car has an extra valve for extracting air, although I've never used Nitrogen...............

[ard]

Originally Posted by Danish-M

It's a rip off since there is no second valve to extract the already existing air out of the tire.
My NT03's on my race car has an extra valve for extracting air, although I've never used Nitrogen...............

Indeed.

Actually I thought of this- I suppose you could do repetitive fill/purges (3,4,5?) with a tank of N2 to get it closer to pure.

Or just punch a hole in the tire to purge and plug it when done!