Nitrogen in car tires

[HowAboutThis]

Originally Posted by Snagglefoot
Just checking what Bitgoers are seeing at their tire shops. Some of the shops in the area provide "nitrogen fills". I checked out one shop and I see all they have is a canister on the inlet to the air compressor that allegedly strips out the oxygen and provides almost pure nitrogen. Air is already 78% nitrogen, 21% oxygen and the last 1% is all the other stuff.

I'm not really convinced that canister is in good shape.

I checked an invoice and they charged $3.50 per tire for this. Have you experienced this anywhere? Sounds like a rip off.


It's a total waste of money unless it's "free" or you're racing, IMO. I've added 0 pounds of air in 6 months to my car's tires with regular air. I'll have to add again when it starts getting cold, then it will stabilize again.

 

[Shannow]

Originally Posted by AZjeff

This comes up like clockwork. Someone had a really good explanation, Shannow maybe?


https://www.bobistheoilguy.com/foru...nitrogen-versus-air-5th-gear#Post4788559

 

[Ducked]

Originally Posted by CR94

Originally Posted by Ducked
What would stop the oxygen in the air permeating into the tyre? I think its supposed to work both ways.


It will, but NET oxygen flow will be outward, because of the higher partial pressure of oxygen in the tire. Which means I admittedly oversimplified when I said nitrogen percentage will increase to "practically 100%." It will increase above the percentage in air, as most (not all) of the oxygen and water vapor permeates out.

Edhackett's answer was good, although more detailed than I assumed you expected.


Yeh, I liked it, because I thought it was accurate. Yours, not so much, because I thought it wasn't.

Your subsequent post above is directly contradicted by Edhackett's in several places.

 

[Garak]

Originally Posted by edhackett
I think that the fact that people see lower leakage is that a nitrogen fill usually comes with replacement of the cheesy plastic valve caps with higher quality ones with an o-ring seal.

Ed, believe it or not, sometimes you can get lucky and find plastic valve caps that do have an o-ring seal. Granted, they're not easy to find, but I had a bag of them at one time.

 

[Traction]

I can't count the ways wheels, and tires find a way to leak. Even the tire itself is one example, just by where some manufacturers decide to put the stupid bar code sticker on the main sealing surface of the tire. Cooper is the worst, with random positions, sticking out from the wheel flange, and sometime they put 2 bar code stickers on. Clip on wheel weights cause leaks, along with corroded valve stems, rim flanges, and even the surface of the bead seat on the tire. Michelin has the best bead seats by far, along with the best inner liner. Part of why they last so long. They rot from the outside in. Some quality wheels will never corrode, or leak, but so many others are toast in less than 3 years. Believe it or not, wet compressed air will NEVER be better that Nitrogen for filling tires.

 

[Garak]

That last sentence may be true. However, we've never seen it demonstrated that nitrogen will ever be better than air for filling consumer grade tires, either.

 

[redbone3]

I have my own compressor and live in Reno, NV. With the low humidity here the compressed air is pretty [censored] dry to start with.

 

[Shannow]

Originally Posted by Traction
Believe it or not, wet compressed air will NEVER be better that Nitrogen for filling tires.


Believe it or not....no one has EVER said it would be...have they ???

 

[brages]

Originally Posted by circuitsmith

It seems to me carbon dioxide would make for a low seepage tire fill.


CO2 is in fact very bad for seepage. I use CO2 canisters for quick inflation when I get a flat on my bicycle. The tire inflated with CO2 will be nearly flat the next day. Reinflated with air, it holds pressure normally.

Of course, a car tire is a lot thicker than a bike tube, but I think CO2 (for what reason I don't know) seeps out especially fast.

 

[redbone3]

Originally Posted by brages
Originally Posted by circuitsmith

It seems to me carbon dioxide would make for a low seepage tire fill.


CO2 is in fact very bad for seepage. I use CO2 canisters for quick inflation when I get a flat on my bicycle. The tire inflated with CO2 will be nearly flat the next day. Reinflated with air, it holds pressure normally.

Of course, a car tire is a lot thicker than a bike tube, but I think CO2 (for what reason I don't know) seeps out especially fast.


Carbon Dioxide and water vapor yields carbonic acid. Can't be a good thing.

 

[circuitsmith]

Originally Posted by brages
CO2 is in fact very bad for seepage.


Alas, I found that out shortly after I made that post.
It quickly diffuses right through rubber. Molecule size ain't everything.

 

[Traction]

Filling a dry chemical fire extinguisher with wet compressed air probably would much easier and cheaper, but not the best idea. I charge my two reusable 1979 vintage 2 1/2 gallon stainless water fire extinguishers with Nitrogen to 100 psi, and RO water.

 

[CR94]

Originally Posted by Ducked
Originally Posted by CR94

Originally Posted by Ducked
What would stop the oxygen in the air permeating into the tyre? I think its supposed to work both ways.


It will, but NET oxygen flow will be outward, because of the higher partial pressure of oxygen in the tire. Which means I admittedly oversimplified when I said nitrogen percentage will increase to "practically 100%." It will increase above the percentage in air, as most (not all) of the oxygen and water vapor permeates out.

Edhackett's answer was good, although more detailed than I assumed you expected.


Yeh, I liked it, because I thought it was accurate. Yours, not so much, because I thought it wasn't.

Your subsequent post above is directly contradicted by Edhackett's in several places.
? What places? The only logical explanation I can guess for this --uh-- misunderstanding is that you might've somehow assumed I was referring to a tire initially filled with nitrogen. Otherwise you'd have to believe gases permeate from lower to higher partial pressure, which I never said.

 

[Shannow]

Originally Posted by Traction
Filling a dry chemical fire extinguisher with wet compressed air probably would much easier and cheaper, but not the best idea. I charge my two reusable 1979 vintage 2 1/2 gallon stainless water fire extinguishers with Nitrogen to 100 psi, and RO water.



annnnddddd.....???

This, and the other thread was about the N2 boondoggle (or the 4%O2 version in your set-up), versus regular air.

Not dry powder fire extinguishers or shock absorbers...tyres...on cars...

 

[Nyogtha]

Industrially, every petroleum refinery I workedin used pressurized CO2 cylinders to on-demand pressurize dry chemical fire extinguishers, both in training exercises and in service.

I like Shannow fail to see how that relates to nitrogen vs compressed air in vehicle tires.

I topped off the tires in my wife's Mustang with compressed air from one of the few free air stations left where I live Monday this week. Despite being filled with nitrogen at the dealership, pressures dropped 6 PSI when our recent set of rain storms broke the drought we've had all summer with 100°F ambient temperatures.

 

[Shannow]

Originally Posted by Nyogtha
Industrially, every petroleum refinery I workedin used pressurized CO2 cylinders to on-demand pressurize dry chemical fire extinguishers, both in training exercises and in service.


My second year at the power station I built a ydrogen generating plant and a 13 tonne liquid CO2 storage facility (complete with pressure raising and evaporating ambient air heat exchangers)...taught me a lot about that product (liquid CO2).

Tyres have to obey gas laws...and N2 isn't some magic that defies them.

 

[lenjack]

In the past, I've used a secret, proprietary mix I developed. I'm releasing the formula for the good of all you good folks. It's 78.09% Nitrogen, 20.95% Oxygen, 0.93% Argon, 0.04% CO2. I've named it AIR.

 

[Traction]

Originally Posted by lenjack
In the past, I've used a secret, proprietary mix I developed. I'm releasing the formula for the good of all you good folks. It's 78.09% Nitrogen, 20.95% Oxygen, 0.93% Argon, 0.04% CO2. I've named it AIR.

You forgot the worst part. H2O

 

[Shannow]

Originally Posted by Traction
Originally Posted by lenjack
In the past, I've used a secret, proprietary mix I developed. I'm releasing the formula for the good of all you good folks. It's 78.09% Nitrogen, 20.95% Oxygen, 0.93% Argon, 0.04% CO2. I've named it AIR.

You forgot the worst part. H2O


Worst, as in being forced to eat tenderloin or top loin...i.e. practically there is zero difference to an automobile.

But we've covered that ad nauseum, haven't we ?

 

[CR94]

Originally Posted by Traction

You forgot the worst part. H2O
Which in realistic concentration will soon mostly permeate its way out of the tire, faster than O2 does. The remaining H2O vapor follows standard gas laws, just like other air constituents.