As pictured here, nitrogen has larger molecules than oxygen. In theory, this makes it less likely to escape through the semi-permeable tire liner, causing the tire to lose less pressure over the same time interval as regular air.
Nitrogen is considered a “drier” gas compared to compressed air; the lack of water vapor creates more stable pressure within the tire and corrosion (aka “oxidation”) is less likely to build up on your wheel finish or your TPMS sensors.
As it is, regular compressed air is made up of 78% nitrogen. To achieve the benefits of nitrogen, the concentration has to be at or higher than 93%. To reach this level of concentration, tires often have to be purged multiple times. If your nitrogen-filled tires are low on pressure and nitrogen is unavailable, it’s perfectly safe to fill them with regular air. However, to continually maintain these benefits, the tire will later have to be purged and refilled with nitrogen.
Regardless of how stable nitrogen is in theory, your tires will still lose pressure over time; nitrogen is not immune to the typical expansion and contraction of pressure in a tire due to temperature changes. While some automotive shops will fill your tires with nitrogen for free, many will charge. This means you may end up paying more to fil your tires, which will still need to be checked frequently.
How do I know if my tires have nitrogen in them now?
The most common way to determine if your tires have compressed air or nitrogen is by the color of your tires’ valve caps.
- A nitrogen-filled tire will likely have a green-colored valve cap or include an “N2” emblem.
- A typical air-filled tire will have the more traditional black or chrome valve cap.
Discount Tire’s recommendation
Rather than spending the extra money to have your tires serviced with nitrogen, we recommend using regular air and checking your tires’ pressure once a month. This will eliminate the worry of underinflation, which is one of the primary benefits attributed to nitrogen-inflated tires.
If you need assistance checking your air pressure, stop by your local Discount Tire for a free air pressure check and adjustment. Let’s get you taken care of!