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  #21  
Old 31 May 2011, 01:45 AM
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ganzfeld ganzfeld is offline
 
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Plastic canisters that supposedly fill a certain dark beer in a can or bottle with nitrogen actually fill it with about 80% nitrogen and 20% oxygen... Hmm, proportion sounds familiar. I wonder if some clever folks are selling "80% nitrogen" at a slightly higher rate than what the rest of us call air.

Last edited by ganzfeld; 31 May 2011 at 01:53 AM.
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  #22  
Old 31 May 2011, 01:47 PM
overyonder overyonder is offline
 
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What I find amusing is that there's no real good way to remove all of the old air from inside the tire when filling it. They don't use a vacuum pump and draw out all the old air out. The easiest way to fill a tire with only one gas would be to dismount the tire, and force-flush the tire with Nitrogen (or other) and seat the tire on the rim while it's being flushed. And I can pretty much guarantee that shop guys don't dismount a tire when filling with only Nitrogen!

Rust inside the rim? Doesn't happen all that much, especially for a 5-year ownership of a vehicle.

Tires get dry-rotted rather quickly from exposure to elements (specifically, the sun). Oxygen/moisture is a MUCH lower concern than that.

I've had a 2000 Honda Civic with the original tires. It was owned for its first nine years by my mom, who drove it 2k miles a year, and kept it garaged. Everything on this car is original, including the 11-y-old battery. Only thing I've changed is the O2 sensor and the AC pressure switch.

The tires are still in excellent shape but since I've brought it to SC from Canada, the tires are showing a bit of aging on the outside.

FWIW... I'd never pay a dime extra for a nitrogen fill. Waste of money.

O_Y
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  #23  
Old 31 May 2011, 06:12 PM
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Roadsterboy Roadsterboy is offline
 
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Quote:
Originally Posted by overyonder View Post
I've had a 2000 Honda Civic with the original tires. It was owned for its first nine years by my mom, who drove it 2k miles a year, and kept it garaged. Everything on this car is original, including the 11-y-old battery. Only thing I've changed is the O2 sensor and the AC pressure switch.

The tires are still in excellent shape but since I've brought it to SC from Canada, the tires are showing a bit of aging on the outside.
Change those tires as soon as you can. Visible dry rot and tread depth aren't the only measurements of a tire's lifespan-they deteriorate even if you keep the car garaged, and you're under a pretty serious risk of a blowout. Plus, at eleven years old they're likely to be rock hard and offer very diminished traction.

Seriously, you need to replace them ASAP if you plan on actually driving this car regularly. Even cheap Wal-Mart brand tires are a better bet than the ones you have.

-RB
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  #24  
Old 31 May 2011, 06:55 PM
overyonder overyonder is offline
 
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They are not dry-rotted. I know what dry-rotting is, trust me.

This is dry-rotting: http://c.photoshelter.com/img-get/I0...ubber-Tire.jpg

O_Y
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Originally Posted by Roadsterboy View Post
Change those tires as soon as you can. Visible dry rot and tread depth aren't the only measurements of a tire's lifespan-they deteriorate even if you keep the car garaged, and you're under a pretty serious risk of a blowout. Plus, at eleven years old they're likely to be rock hard and offer very diminished traction.

Seriously, you need to replace them ASAP if you plan on actually driving this car regularly. Even cheap Wal-Mart brand tires are a better bet than the ones you have.

-RB
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  #25  
Old 31 May 2011, 07:51 PM
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Thank you, I know what dry rot looks like as well. I'll reiterate: visible dry rot (what you see on the outside of the tire) is not the only thing that will determine whether or not a tire is rotting-they rot from the inside as well.

Believe me, I've had it happen several times now with my father's MG, which is also garage kept and does about 2-3,000 miles a year. The tires it came with started going bad a few years ago, even though they looked fine on the outside-they were all dry rotting along the beads, and they were all about eight years old at that point.

-RB
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  #26  
Old 31 May 2011, 08:42 PM
RichardM RichardM is offline
 
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See this from Discount Tire: http://www.discounttire.com/dtcs/infoTireLife.dos
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  #27  
Old 31 May 2011, 08:56 PM
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Tire Rack makes the same recommendation-for some reason my link didn't show (user error, I'm sure-I backtracked and got interrupted several times).
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  #28  
Old 31 May 2011, 11:37 PM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by overyonder View Post
What I find amusing is that there's no real good way to remove all of the old air from inside the tire when filling it. They don't use a vacuum pump and draw out all the old air out. The easiest way to fill a tire with only one gas would be to dismount the tire, and force-flush the tire with Nitrogen (or other) and seat the tire on the rim while it's being flushed. And I can pretty much guarantee that shop guys don't dismount a tire when filling with only Nitrogen!
This is a common problem in chem labs, exchanging air in a vessel with an inert atmosphere. The solutions is easy enough even without a vacuum pump. For a tire you fill and vent the tire a couple times. Figure the tire is at 15 PSI (absolute pressure) and you take it to the recommended 45 PSI (again absolute, not gauge, pressure). The tire now has about 6% oxygen in it. You vent and fill again with pure nitrogen and the oxygen content will be around 2%. The water content will be well below 1%. Repeat however many times you wish. Each fill / vent cycle will reduce the oxygen content by about 2/3rds of the previous cycle.
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  #29  
Old 31 May 2011, 11:51 PM
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ganzfeld ganzfeld is offline
 
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Icon81

After fifteen such cycles, the resulting homeopathic gas cures lung cancer and reduces the need to breathe on a regular basis.
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  #30  
Old 01 June 2011, 01:15 PM
overyonder overyonder is offline
 
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Quote:
Originally Posted by jimmy101_again View Post
This is a common problem in chem labs, exchanging air in a vessel with an inert atmosphere. The solutions is easy enough even without a vacuum pump. For a tire you fill and vent the tire a couple times. Figure the tire is at 15 PSI (absolute pressure) and you take it to the recommended 45 PSI (again absolute, not gauge, pressure). The tire now has about 6% oxygen in it. You vent and fill again with pure nitrogen and the oxygen content will be around 2%. The water content will be well below 1%. Repeat however many times you wish. Each fill / vent cycle will reduce the oxygen content by about 2/3rds of the previous cycle.
All nice and good. You reckon that shop guys do that? [Answer is: heck no!]

O_Y
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  #31  
Old 01 June 2011, 02:23 PM
UrbanLegends101 UrbanLegends101 is offline
 
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Interesting shift in the thread to old tires.

I just replaced the four tires on the truck, a 2003 model, original tires. 48K miles and still many a mile left on the tires, but there were beginning to show a bit of dry rot on the thread edges. I've have probably gone longer with the tires, if I were the only driver, but I figured with wife driving the truck, I'd better change them out. We get summer temps routinely in the 110-120 degree F range, so I figured new tires were cheaper than a road accident.

121 degrees coming to work this morning, per the thermometer in the Jeep dash.
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  #32  
Old 01 June 2011, 02:30 PM
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A Turtle Named Mack A Turtle Named Mack is offline
 
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Quote:
Originally Posted by overyonder View Post
All nice and good. You reckon that shop guys do that? [Answer is: heck no!]

O_Y
Do you even think the tanks they use for a nitrogen fill are anything other than regular air, i.e. 80% nitrogen? I really don't know, but would anyone know the difference if they just used air? There isn't some sort of certification, AFAIK.
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  #33  
Old 01 June 2011, 03:06 PM
overyonder overyonder is offline
 
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Quote:
Originally Posted by A Turtle Named Mack View Post
Do you even think the tanks they use for a nitrogen fill are anything other than regular air, i.e. 80% nitrogen? I really don't know, but would anyone know the difference if they just used air? There isn't some sort of certification, AFAIK.
Well if it's coming from the shop air (regular compressed air) versus a cart-tank, that's a different story... Of course they could still fill a cart-tank to ~150 PSI with shop air to make pretend they were using N2. N2 is widely available at gas shops (I mean the welding shops, not the gasoline stations).

O_Y
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  #34  
Old 01 June 2011, 03:21 PM
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Quote:
Originally Posted by ganzfeld View Post
Plastic canisters that supposedly fill a certain dark beer in a can or bottle with nitrogen ...
When I first read about this in an English newspaper they commented it something like this: "That's typical Irish, getting the head at the bottom of the can".
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  #35  
Old 01 June 2011, 03:30 PM
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A Turtle Named Mack A Turtle Named Mack is offline
 
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Hey, I just figured out a way to fill the tire with nearly pure, very dry N2 gas. When you are mounting the tire, put in a quart or so of liquid nitrogen, then complete the seal. Then as the pressure mounts, bleed off the excess pressure (this is very important to avoid explosion). Keep the stem at the top so that the warmer 'old air' is bled off preferentially, rather than the all-nitrogen evaporate which wil be very cold.

CAUTION - please do not try this - at home or anywhere else. This is a stupid dangerous idea, both because the pressure would build very quickly, and because the extreme cold of liquid nitrogen would severely freeze the rubber of the tire and compromise its integrity.
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  #36  
Old 01 June 2011, 05:10 PM
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Ali Infree Ali Infree is offline
 
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On the other hand, Turtle, I would like to see Mythbusters try that one!
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  #37  
Old 01 June 2011, 05:18 PM
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A Turtle Named Mack A Turtle Named Mack is offline
 
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Originally Posted by Ali Infree View Post
On the other hand, Turtle, I would like to see Mythbusters try that one!
Oh, hell, yeah! Or the Jackass team.
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  #38  
Old 01 June 2011, 06:27 PM
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Der Induktionator Der Induktionator is offline
 
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Quote:
Originally Posted by A Turtle Named Mack View Post
Hey, I just figured out a way to fill the tire with nearly pure, very dry N2 gas. ....[/I]
I had a couple ideas:
- With the valve as close to the top as possible, slowly fill the tire with a heavy gas, like xenon, slowly forcing the lighter air out the top (a 'T' fitting would be needed). Then turn the tire upside down and repeat, this time the nitrogen displaces the xenon gas.

- Alternative to the above but the other way around with a very light gas like helium.

- put the whole tire + rim (With the valve open) inside a chamber and pull a vacuum on it, the harder the better. Then re-pressurize the chamber up to a bit below the desired ~30 PSI with nitrogen, and close the valve on the tire. Depressurize the chamber to atmospheric pressure, then top off the tire as needed. The closer the tire fits in the chamber the less gas gets wasted.
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  #39  
Old 01 June 2011, 07:10 PM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by overyonder View Post
All nice and good. You reckon that shop guys do that? [Answer is: heck no!]

O_Y
Even if they don't, filling once with pure N2 would give you a tire containing about 1/3 the amount of oxygen and water compared to normal filling with air.
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  #40  
Old 25 July 2011, 05:55 PM
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The reason to run nitrogen in your tires is to decrease the effects of heat while driving on the tires. Nitrogen will not react as regular air, air expands and contracts way way more than nitrogen, as much as 5-8lbs increase when driving interstate speeds, exspecially in the south like here in Texas. Also cold and winter is the same, put in 32 lbs of air and it can deflate down to 16-18 lbs due to the cold temp, notrogen remains pretty stable at any perceivable operating temperatures, from 140's to _40's.put in 36lbs and it will remain 36lbs.always....one cannot say that with compressed air.
that is the reason we run nitrogen in our tires.
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