Nitrogen in Your Tires
Try to find a auto dealership that doesn’t include this in their fees. They’ll fill your tires with 100% nitrogen, claiming that your tires will hold their pressure longer. For this service, you’ll pay a few hundred dollars. It’s $299 to $399 fee around here.
Here’s the thing: Plain ‘ol air is roughly 78% nitrogen. Oxygen makes up nearly another 21%, with Argon picking up most of the remainder, leaving trace amounts of other gasses to fill up the last fractions of a percent.
Oh, but that’s only 78%, you’ll hear back, which leaves the other 22% to leak out, you see, because nitrogen molecules are larger, and are therefore less able to leak out.
Okay, well since we’re basically only talking about nitrogen versus oxygen, exactly how much larger is nitrogen? We’re measuring in picometers (one trillionth of a meter, or 10-12 meters), and a quick google search reveals that nitrogen (N2) is 300 picometers, while oxygen (O2) is 292 picometers, a difference of only 8 picometers!
Well that’s a pretty thin window. Somehow, then, when molecules leak out, they must be doing so through a gap somewhere between these two values, so between 293 and 299 picometers, inclusive. Any larger or smaller gaps will negate nitrogen’s supposed benefit here.
There’s often a thin sliver of truth behind a good scam, however, and this is no different. According to Consumer Reports:
The average loss of air-filled tires was just 3.5 psi from the initial 30 psi setting. Nitrogen-filled tires lost an average of 2.2 psi.
The results show that nitrogen does reduce pressure loss, but the reduction was only a 1.3-psi difference from air-filled tires over an entire year.
Should You Use Nitrogen in Your Car Tires? https://www.consumerreports.org/cars/tire-buying-maintenance/should-you-use-nitrogen-in-car-tires-a6260003694/
$300 bucks … to lose 1.3 psi less … over a year. Silly.