Nitrogen?
- Thread starter TSHACK
- Start date
- Status
Originally Posted By: moribundman
Originally Posted By: XS650
If the people touting nitrogen use in tires are correct, a tire is very effective at separating nitrogen from oxygen.
Also, a car tire is usually filled with about 2 bar above ambient pressure. Ambient pressure is about 1 bar. Since a tire already contains ambient air, and because air is not being evacuated when the tire is "filled," the tire will contain only about 66% added nitrogen, while still containing 33% air. That means the total nitrogen content is increased by only about 15% over a tire filled with plain old air.
Initially, the conditions you describe are somewhat valid. When the tire is first mounted and inflated, a bit of atmospheric air will be included in the N2 fill.
After the tires are mounted on the car, 2 or more purge cycles are done. The tire fill is forcefully sucked out and then reinflated with nitrogen. This procedure will insure that most of the tire's contents will be dry nitrogen.
Originally Posted By: XS650
If the people touting nitrogen use in tires are correct, a tire is very effective at separating nitrogen from oxygen.
Also, a car tire is usually filled with about 2 bar above ambient pressure. Ambient pressure is about 1 bar. Since a tire already contains ambient air, and because air is not being evacuated when the tire is "filled," the tire will contain only about 66% added nitrogen, while still containing 33% air. That means the total nitrogen content is increased by only about 15% over a tire filled with plain old air.
Initially, the conditions you describe are somewhat valid. When the tire is first mounted and inflated, a bit of atmospheric air will be included in the N2 fill.
After the tires are mounted on the car, 2 or more purge cycles are done. The tire fill is forcefully sucked out and then reinflated with nitrogen. This procedure will insure that most of the tire's contents will be dry nitrogen.
Kestas
Staff member
That seems like a lot of trouble just to get the last dregs of oxygen or moisture out of the tire. Do all the tire places go through this protracted task for each tire?... is it worth it (their time and your expense)? I think not.
I don't know Kestas, the place I go to does. I have not asked if this N2 procedure is a company policy or the N2 machine manufacturer recommends it.
- Joined
- Jun 2, 2003
- Messages
- 23,591
Originally Posted By: harry j
After the tires are mounted on the car, 2 or more purge cycles are done. The tire fill is forcefully sucked out and then reinflated with nitrogen. This procedure will insure that most of the tire's contents will be dry nitrogen.
Uh, if they suck out the tire fill, how does the tire still seal against the rim/hump/safety bead while under negative pressure?
After the tires are mounted on the car, 2 or more purge cycles are done. The tire fill is forcefully sucked out and then reinflated with nitrogen. This procedure will insure that most of the tire's contents will be dry nitrogen.
Uh, if they suck out the tire fill, how does the tire still seal against the rim/hump/safety bead while under negative pressure?
First of all, if you remove the needle valve from the stem and fill the tire(with the air hose) with out a chuck/fitting and only the air hose, the tire will fill in a hurry and will seat the bead. I'll bet few people have tried this!
- Joined
- Jun 2, 2003
- Messages
- 23,591
Char Baby, what's that got to do with successfully "sucking out the tire fill" and "reinflating with nitrogen?"
You said "First of all." What's "second?"
Let's say you mean to say a tire will seal without air pressure having to be above ambient pressure (1 bar), which I doubt is the case. Do you seriously believe that it is possible to pump out the ambient air to any degree out of the tire with the tire still sealing against the rim?
Engineers, please!
You said "First of all." What's "second?"
Let's say you mean to say a tire will seal without air pressure having to be above ambient pressure (1 bar), which I doubt is the case. Do you seriously believe that it is possible to pump out the ambient air to any degree out of the tire with the tire still sealing against the rim?
Engineers, please!
Having installed may a tire in my time I can tell it can easily take over 25psi to stretch the tire over the bead lock.
I wouldn't be surprised if you could pull 10hg of vacuum and still keep is sealed.
I have no idea how low they would pull down the pressure to evacuate a tire.Maybe its only 1hg???
I would suspect many shops wouldn't evacuate at all. I wouldn't pay extra for Nitrogen fill.
I wouldn't be surprised if you could pull 10hg of vacuum and still keep is sealed.
I have no idea how low they would pull down the pressure to evacuate a tire.Maybe its only 1hg???
I would suspect many shops wouldn't evacuate at all. I wouldn't pay extra for Nitrogen fill.
Originally Posted By: harry j
I don't know Kestas, the place I go to does. I have not asked if this N2 procedure is a company policy or the N2 machine manufacturer recommends it.
Only when the customer is watching.
I don't know Kestas, the place I go to does. I have not asked if this N2 procedure is a company policy or the N2 machine manufacturer recommends it.
Only when the customer is watching.
- Joined
- Jun 2, 2003
- Messages
- 23,591
Is there anyone else besides harry j here who claims that all, some, or even any air is being evacuated before or while the tire is being inflated with nitrogen? I have had my tires inflated with nitrogen several times until about 12 years ago. I don't remember observing any purge cycle, but it's been over a decade since then...
Originally Posted By: moribundman
Originally Posted By: harry j
After the tires are mounted on the car, 2 or more purge cycles are done. The tire fill is forcefully sucked out and then reinflated with nitrogen. This procedure will insure that most of the tire's contents will be dry nitrogen.
Uh, if they suck out the tire fill, how does the tire still seal against the rim/hump/safety bead while under negative pressure?
I am not sure what the mechanics are, just that the rim/tire seal remains intact during the procedure and after.
Originally Posted By: harry j
After the tires are mounted on the car, 2 or more purge cycles are done. The tire fill is forcefully sucked out and then reinflated with nitrogen. This procedure will insure that most of the tire's contents will be dry nitrogen.
Uh, if they suck out the tire fill, how does the tire still seal against the rim/hump/safety bead while under negative pressure?
I am not sure what the mechanics are, just that the rim/tire seal remains intact during the procedure and after.
- Status
