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Dréa 3/10/2012

2006 Volkswagen Beetle 2.5 5 Cyl 2.50L

Preventive Maintenance

Do green valve caps on tires mean the tires are nitrogen and not air filled?

When I bought my 2006 VW New Beetle about a month ago, there was only one valve cap on one of the tires, but it was green. I went into Kragen today to get a set of 4 caps, but the employee said that green caps usually means the tire is nitrogen filled. Is that true? If so, how do I go about finding out if they are or not?

2 Answers

63 Volvo

63 Volvo 3/10/2012

Yes it does on Michelins forsure.


CVO 3/12/2012

I agree with 63 Volvo.
Recently, colored plastic valve caps have appeared. Certain automobile tire dealerships are promoting the use of dry nitrogen to inflate tires. Dealers claim that eliminating oxygen and water will prolong the life of both tires and wheels. These dealers install green caps to signify that the tires are filled with nearly pure (typically about 95%) nitrogen. In contrast, regular air is approximately 78% nitrogen. The moisture in the air-filled tires condenses in below-freezing temperatures and causes a sudden drop in tire pressure. Dry-nitrogen filling helps prevent this problem. As an alternative to green nitrogen-ID (nitrogen-identification) caps, green nitrogen-ID O-rings to be installed on valve stems under the caps, while still using black- or metallic-colored caps, are also available [3].


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