Here's What a Green Cap on Your Tire Valve Means | Family Handyman

By Karuna Eberl

Updated on Sep. 13, 2024

Nitrogen is a trendy, techie alternative for filling tires, but it costs more. Here's how to know if it's a fit for your vehicle and driving style.

The benefits of inflating car and truck tires with nitrogen gas is trending, but the technology isn’t necessarily new. Since the 1980s, the FAA has mandated nitrogen be used in aircraft tires. Nitrogen is also commonly used in race cars and heavy-duty mining equipment. But is it worth the extra $20-plus for putting it in your personal vehicle? Here’s how to decide.

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Green caps on tire valve stems signify that the tire is filled with nitrogen instead of regular air.

Pros:

Cons

Pros

Cons

It depends. Nitrogen has benefits, but “for most everyday driving, air is all that is needed,” says Paul Knoll of AmericanMuscle. “However, if the driver seeks more consistent tire pressure and potentially longer tire life with fewer maintenance intervals, nitrogen would be beneficial.”

Family Handyman master technician Bob Lacivita agrees. “It can’t hurt your tires,” he says. “For most drivers, regular compressed air is fine. However, if you live in climates where there are large temperature differences, do a lot of highway driving in warm conditions, or can get nitrogen for a few dollars at local tire store, it would be a good idea.”

Either way, get a good tire pressure gauge and check the tire pressure regularly.

Several months, on average. Tires filled with nitrogen tend to maintain their pressure longer than those filled with ordinary air.

It ranges from around $5 to $10 per tire. Knoll says some service centers also offer unlimited refills for a one-time cost.

Nitrogen for tires is available at many tire shops and automotive service centers.

Yes. It won’t do any harm to mix nitrogen with regular air in your tires, though that may degrade or eliminate the benefits of the nitrogen.