Yes, you can safely put regular air into tires that have been filled with nitrogen. There are no dangerous effects from mixing air and nitrogen in your tires.
Understanding Tire Fillings: Air vs. Nitrogen
Regular air is approximately 78% nitrogen, 21% oxygen, and small amounts of other gases like argon and carbon dioxide. Pure nitrogen filling typically uses nitrogen at 93-95% purity. While nitrogen is often promoted for its benefits in tire longevity, pressure stability, and fuel efficiency due to its larger molecular size and lower moisture content, mixing it with air alters its intended purity.
What Happens When You Mix Them?
When you add regular air to a tire filled with nitrogen:
- Dilution of Purity: The primary effect is that the purity of the nitrogen within the tire becomes diluted. As air (which contains oxygen and other gases) is introduced, the percentage of pure nitrogen decreases.
- Loss of Effectiveness: This dilution means you will lose some of the specialized benefits often associated with pure nitrogen inflation. The advantages, such as more stable tire pressure over time (due to less permeation through the tire wall) and reduced oxidation of the tire's internal components, diminish as oxygen and moisture are reintroduced.
- No Safety Risk: Importantly, there are no safety hazards or risks involved in mixing air with nitrogen. Your tires will still function normally, and your vehicle's handling will not be compromised.
Practical Considerations
While it's safe to mix air and nitrogen, the question then becomes whether the benefits of having nitrogen-filled tires are still worthwhile once diluted. For most everyday drivers, the difference between pure nitrogen and an air-nitrogen mixture becomes negligible. If you initially opted for nitrogen for its specific advantages, consistently topping off with air will effectively turn your nitrogen-filled tires into regular air-filled tires over time.
Key Takeaways:
- Safety First: Mixing air and nitrogen is completely safe.
- Purity Compromise: The main drawback is the dilution of nitrogen purity, which reduces its specific benefits.
- Convenience: If you're on the road and need to add air, there's no need to seek out a nitrogen source. Use regular compressed air without worry.
Ultimately, topping off your nitrogen-filled tires with air is a convenient and safe solution, though it does dilute the specialized properties of nitrogen.
