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What Do Green Caps on Tires Mean?
When you see a tire with a green cap, it indicates that the tire is filled with nitrogen rather than regular air. Why nitrogen? Nitrogen helps tires stay inflated longer and more consistently compared to regular air. This has several advantages, such as improved fuel efficiency and extended tire life.
Why Nitrogen-Filled Tires Have a Green Cap On Them?
The green cap is a quick visual indicator for vehicle owners and service technicians to recognize that the tire contains nitrogen.
What NHTSA Says About Using Nitrogen In Tires?
The National Highway Traffic Safety Administration (NHTSA) has conducted studies on the use of nitrogen in tires. These studies found that nitrogen reduces tire degradation by limiting oxidation. Oxidation can make rubber brittle and lead to tire damage when exposed to oxygen in regular air.
Moreover, nitrogen seeps out of tires more slowly than air, which helps maintain better pressure inside the tire, easier handling, more even tread wear, and longer tire life. However, these benefits are not very significant.
Benefits of Using Nitrogen In Tires
- Consistent Tire Pressure: Nitrogen is slower to escape from tires than oxygen, leading to more consistent tire inflation pressure over time.
- Less Moisture Inside Tires: Nitrogen use results in less moisture inside the tires, which is beneficial for the internal components.
- Reduced Oxidation: With nitrogen, there’s no risk of oxidation due to the lack of oxygen, potentially prolonging tire life.
Drawbacks of Using Nitrogen In Tires
While nitrogen in tires offers several benefits, there are also reasons why you might opt for regular air:
- Accessibility and Affordability: Air is more readily available and usually free at many gas stations and service centers. In contrast, nitrogen filling stations can be harder to find and charge for their services.
- Compatibility: Air is compatible with all types of tires, offering a hassle-free choice without the need to find specific tires that work with nitrogen.
- Ease of Maintenance: It’s easier to top off your tires with air, especially since nitrogen filling stations are less common. This ease of maintenance is crucial for safe driving and prolonging tire life.
Can I Fill a Green Cap Tire with Regular Air?
Yes, you can fill a nitrogen-filled tire (marked by a green cap) with regular air without causing harm. While this might dilute some benefits of nitrogen, such as slower pressure loss, it’s more important to maintain the correct tire pressure. So, if nitrogen isn’t readily available, it’s perfectly acceptable to use regular air to top off the tires.
What Is the Cost of Filling the Tire with Nitrogen?
For new tires, the cost of filling with nitrogen ranges from $70 to approximately $175 at certain outlets. If you’re converting existing tires to nitrogen, expect to pay up to $30 per tire for draining the air and refilling with nitrogen. After that, a refill may cost you between $5 and $7 per tire.
Will I Get Better Mileage with Nitrogen-Filled Tires?
The impact of nitrogen-filled tires on gas mileage isn’t as significant as often claimed. While nitrogen does help maintain tire pressure more consistently, which is crucial for optimal fuel economy, the actual improvement in gas mileage is marginal. The most effective way to ensure better fuel economy is to maintain proper tire inflation, whether you use nitrogen or air.