Nitrogen in Tires?

I have a Saturn Aura. I love the car and I have always be greatly satisfied with my Saturn dealer’s service. But lately, they have been pushing replacing the air in my tires with nitrogen. Is this a scam? I remember many years ago on your show kidding about a mechanic who used to include charges on his bill for changing the air in a customer’s tires, so I’m a little (OK, A LOT) skeptical. Thanks!

My bad. I should have checked the earlier discussion forums before posting this.

I believe Tom and Ray has a question on this as well. Costco is also on a nitrogen kick (they screw on nice green valve caps) and told me it would prevent my rims from rusting. Service stations don’t carry this stuf, so I pressure up with normal air. Air already is mosly nitrogen anyway, so what is the big deal? I would ignore it all and use whatever air pump is close when you need it.

I wouldn’t bother with N2 for a street car either, the only real difference in the lack of water vapor in the N2. The N2 might help prevent corrosion and give more consistent pressure changes at different temperatures.

It’s a waste of money, and a border-line scam. The air we all breathe, and inflate our tires with, is 78% nitrogen. Why pay money for the extra 22% ? If it’s free, take it. Otherwise, say, “No, thank you.”

Pure nitrogen has a larger molecule than the other elements found in air. This slows down the loss of pressure in the tires due to minute leaks such as around the sealing bead of the tire. This becomes more important if the vehicle is equipped with a tire pressure monitoring system.

Pure nitrogen has no moisture contant. This eliminates the corroding/oxidation of steel/alloy wheels.

Pure nitrogen is more stable than air as the pressure builds in the tire as it heats up. This can be beneficial on vehicles equipped with high speed rated tires.

But if you don’t meet any of this criteria, there’s no benefit in using nitrogen in the tires.