Nitrogen in tires: is it worth it?

Ordinary air is already about 78 percent nitrogen. Most of the rest is oxygen, plus some water vapour. A nitrogen fill removes the oxygen and, more importantly, the moisture.

What nitrogen does well

It leaks more slowly. A tire filled with air typically loses one to two PSI a month. Nitrogen slows that down, but the gain over a year is small, and you still need to check your pressures.

It is dry. Water vapour is what makes tire pressure swing with temperature. Dry gas is steadier. That is why racing teams and airlines use nitrogen: their tires see extreme heat, and aircraft tires also need a gas that will not feed a fire.

What it does not do

Dry compressed air behaves almost the same as nitrogen in everyday driving. A shop with proper air dryers is already giving you most of the benefit. The difference shows up when the air is damp, like a small compressor in the driveway on a humid day.

Passenger car and truck tires rarely get hot enough for the moisture to matter the way it does on a race track.

So is it worth it?

For most drivers, nitrogen is a small improvement, not a necessity. It makes the most sense if a vehicle sits for long stretches, or if you want pressures as steady as possible.

Either way, the habit that matters is the same: check your tire pressures once a month. Ask at the counter about nitrogen fills.