# Nitrogen in car tires?

**URL:** <https://boards.straightdope.com/t/nitrogen-in-car-tires/471909>\
**Category:** Factual Questions\
**Created:** [November 9, 2008, 4:16pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909 "2008-11-09T16:16:43Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\
**Post date:** [November 9, 2008, 4:16pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909/1 "2008-11-09T16:16:43Z")

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A friend just dropped by to show me his new car. It’s nice and all, but what I noticed was the tires are inflated with Nitrogen. The only advantage I can see is less oxidation and damage from the inside due to the lack of Oxygen or perhaps less diffusion of gas out of the tire due to larger average size of the N2 molecule than air generally. The disadvantage is getting the tires inflated when low - they have a special nozzle for Nitrogen only. What’s the Straight Dope on this?

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [November 9, 2008, 4:22pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909/2 "2008-11-09T16:22:28Z")

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Cecil did a column about this subject, with a discussion thread [here](http://boards.straightdope.com/sdmb/showthread.php?t=489376).

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**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\
**Post date:** [November 9, 2008, 4:38pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909/3 "2008-11-09T16:38:48Z")

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Though maybe not quite as good, you can buy special devices that fill your tires with 78% nitrogen.

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**Author:** ![Bill\_Door](https://avatars.discourse-cdn.com/v4/letter/b/50afbb/32.png) [@Bill\_Door](https://boards.straightdope.com/u/Bill_Door)\
**Post date:** [November 9, 2008, 4:41pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909/4 "2008-11-09T16:41:29Z")

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> [@Crafter\_Man](#):
>
> Though maybe not quite as good, you can buy special devices that fill your tires with 78% nitrogen.

And your tires could have some kind of diffusion filters that would, over time, increase the percentage of notrogen inside them.

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**Author:** ![WhyNot](https://avatars.discourse-cdn.com/v4/letter/w/c77e96/32.png) [@WhyNot](https://boards.straightdope.com/u/WhyNot)\
**Post date:** [November 9, 2008, 4:56pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909/5 "2008-11-09T16:56:59Z")

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Costco’s tires are all Nitrogen filled now, but I can put regular air in them if I want to. Of course, it will dilute the benefits you’ve mentioned, but it won’t cause damage or anything, according to the pamphlet they gave me when I bought the tires. No special valve, but they do have green caps instead of black.

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**Author:** ![flex727](https://avatars.discourse-cdn.com/v4/letter/f/258eb7/32.png) [@flex727](https://boards.straightdope.com/u/flex727)\
**Post date:** [November 9, 2008, 5:38pm UTC](https://boards.straightdope.com/t/nitrogen-in-car-tires/471909/6 "2008-11-09T17:38:00Z")

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> [@Q.E.D](#):
>
> Cecil did a column about this subject, with a discussion thread [here](http://boards.straightdope.com/sdmb/showthread.php?t=489376).

:smack: Somehow I missed that column. Thanks for gently pointing me in that direction.