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Engine & Transmission Tips • Issue 40

Nitrogen Filled Tires

Costs. Benefits. Should You Do it?

What does Nitrogen gas (N2) in your tires provide over regular gas station compressed air?

uth nitrogen valve stem hero

The truth is… divided.

There are two camps, divided about the benefits of putting nitrogen gas in your vehicle’s tires. The first group has decided you have to fill your tires often enough that it is a waste of time and money. The second group understands the science, and find the investment worth-while.

But, you need to be diligent either way.

uth nitrogen tire filling machine AS168829885

Nitrogen-filled tires lose tire pressure much more slowly than traditional air-filled tires. This is due to the fact that nitrogen molecules are larger, and the pure gas is more structured, so it escapes at a slower rate.

The belief is that you will get better gas mileage and a fuller tire life because you’re always riding on properly inflated tires.

Pure nitrogen is also believed to thwart tire dry rot, because there it is a dry gas with no excess moisture, as found is always found in ordinary compressed air.

The naysayers believe the above-mentioned benefits aren’t great enough to justify the cost or perceived inconvenience. Nearly true if you let a dealership gouge you with the purchase of a new, or pre-owned, vehicle, which can cost you from $75 to as much as $175 per tire. Less true if you take your car to a reputable shop, where it will cost less. You’ll pay about $35 per tire for the conversion, (drain the air out and replace it with nitrogen), and top-offs will then cost between $7–$10 per tire.

Even with the statement of pure nitrogen, the mix never really gets over 95%, but there are far less ancillary components like oxygen, water vapor, carbon dioxide, and other potentially corrosive gases, than in regular compressed air, weighing in at 20%.

The most prevalent causes of tires slowly deflating are significant swings in outside temperature, and normal driving. In some regions of the U.S. The daytime temperature can be above 70 degrees, while the nighttime temperature below 40 degrees. Typical compressed air expands and contracts more than nitrogen within that temperature range to affect tires both visibly and performance-wise.

uth nitrogen valve stem capThe act of simply driving increased the tire’s pressure enough that whatever is used to fill the tire is pushed out through microscopic openings and pores to the point that the average air-filled tire loses about one-to-two PSI (pound of pressure per square inch), per month; nitrogen-filled tires a little less.

The takeaway is that the average car owner refills their tires with the seasons, or about four times a year. With nitrogen-filled tires, that may be reduced to just two times a year, but will cost $25–$40.

Probably the coolest thing about filling your tires with nitrogen is the little green valve stem cap you get to display on your rims.

Check this NITROFILL Authorized Dealer Finder on-line tool to find a reputable shop.


Scenarios where nitrogen gas is an actual benefit:

  • Vehicles that exist in climates with wide temperature swings
  • Vehicles that are stored for long periods of time
  • Vehicles that are not driven frequently
  • Vehicles own by elderly or mobility-challenged persons
  • Vehicles owned by lazy people who never check their tires’ pressure
  • Vehicles where loss of tire stability is dangerous, i.e. ambulances
  • Performance vehicles, like track race cars or street racing rigs


Fanatics’ Pros-N-Con:

Pro – You don’t have to check your tire pressure, and you refill less frequently
Con – You have to schedule this service at a shop, taking up time

Pro – You don’t have to get on your knees, and get your hands dirty
Con – You have to pay for what you can find for free at some gas stations

Pro – Nitrogen gas isn’t flammable
Con – Air isn’t flammable either

Pro – You can tell your friends the little green valve stem cap is because you use pure nitrogen in your tires
Con – Those supposed friends will take those caps and put them on their tires with regular air just to mock you.


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