Nitrogen in tires - upsell only or good deal?

I saw an ad for tires that gave a price for the tires with installation included. This was at Costco and included Michelins with a free fill with nitrogen. I have always heard this is just an upsell for the most part but was wondering if there is any real benefit. I hear it expands/contracts less with thermal changes and it less likely to slowly leak because the molecule is larger. Plus there is less oxygen to slowly degrade the insides of the tires. On the other hand, air is mostly nitrogen anyway. How big of a deal does this really make? I have been told that unless you race, it isn’t worthwhile at all.

Also, if you have tires that are on the car a long time but slowly leak as they all do, will oxygen preferentially leak over time and will the gas content in the tire become enriched with nitrogen as tires are topped off over time? Although the molecular weight of oxygen is larger, the molecule is smaller. I guess this could also reduce the rotational inertia of your tires by a TINY amount but again, we are splitting hairs. Is there any merit in this?

Air is 79% nitrogen. I don’t believe there is any advantage for the normal driver.

How is Costco up-selling if it is free? Since their tires are usually lower priced or at least competively priced, does it really matter if they are filled with nitrogen or plain old air? That said the only way I would bother with nitrogen is if it is free.
And yes you are splitting hairs with a subject that has been split to death and back in this and a number of other forums.

How is a “free fill of nitrogen” an upsell?

Well, if you buy the hype, it’s a way to keep you coming back to Costco for service, so it’s not completely altruistic.

I say it’s an up-sell.
Many Ford dealers sell nitrogen …we do not and have no plans to.
Every one who sells it can spout a line of benefits a mile long.
Every one who does not can spout a line a mile long of why you don’t need it.
I have three trucks…all have just air…NONE lose sufficient psi over time !
The only problem I’ve ever had with time deterioration has been due to sun ( UV ) exposure on the 79 that stays parked outside all of the time. Once I bought RV tire covers…problem solved.

Nitrogen is an outstanding way to expand the money making capability of the automobile. Once we are weaned into thinking we are needing it, when electric vehicles with their minimal maintenance requirements come along, service stations will at least have a reason for you come in for regular service…So, .by all means, “fall” for it. The extra income garnered some service providers may show up in better deals for the rest of us…or not.

The only benefit with nitrogen is it contains no moisture. So there’s no chance of corrosion of alloy wheels causing leaks.


The benefits of nitrogen are miniscule. I’d take it for free, but I wouldn’t pay anything for it.

When I bought tires the tire place filled them up with a mixture of 78% nitrogen. I understand that with full fledged racing cars driving high speeds nitrogen filled tires can make a slight difference. Everything I’ve read leads me to believe that for the rest of us it makes a negligible difference.

I always insist on exactly 78% nitrogen in my tires.

Yeah, I know it is free at Costco but it is extra everywhere else from what I have seen. Sounds like it isn’t worth the extra cost if it isn’t free. If free, no harm done and maybe a little benefit.

It’s a total farce, but it’s free. If the cost of the tires is to your satisfaction, let 'em put their free nitrogen in. It’ll do absolutely no harm.

Race teams are required to use nitrogen because it will not feed a fire in the pits should one happen. Compressed air would.

That’s a riot mountainbike!

Race teams use nitrogen only because the pressures in the tires remain more constant during a race.


As Ken Green noted:

Every one who sells it can spout a line of benefits a mile long.
Every one who does not can spout a line a mile long of why you don’t need it.

This is so true!
And for those who do sell it now, they weren’t spouting the line of benefits until they got their “profit increasing nitrogen machine”.

TireRack’s Tech Info page had an interesting comment on the subject:

Pure nitrogen has been used to inflate critical tire applications for years, primarily because it doesn't support moisture or combustion. These include racing tires (IndyCar, Formula 1, NASCAR), aircraft tires (commercial and military) and heavy-duty equipment tires (earthmovers and mining equipment).

‘How is it an upsell if it’s free?’ Come in for the free balance and rotate. Oops, pressure is a bit low in 3 tires. Woah, it has green valve caps, gotta use the nitrogen. Cha-ching, extra fee for topping off the ‘free’ nitrogen fill.

I was still working at the Benz dealer when they got their profit generating machine

Boy, it sure made things more complicated . . .

Every pre-delivery now included hooking the car up that machine. Somehow it would let the air out of the tires, then refill with nitrogen. You would enter the desired pressure, and it would supposedly stop when it was reached. But you still had to double check. It added another few minutes to the job

I laugh when I see those green valve caps. I bet they cost way more than the black caps. Anybody know for sure?

Who’s to say that when the tire gets fixed, because of a nail, it won’t get refilled with good old air instead of nitrogen? Yet the guy doing the repair puts back the green cap. heh heh heh . . .

I put this in the category of, “someday we’ll have them all buying our stuff”’

I started Shoeing horses 35+ years ago and when I started you could only find two types of water in any of the stores. Gallons of drinking water, and gallons of distilled water for making baby formula and using in your steam iron.
Now look at the selection, and they’ve got us paying more for a bottle of water than a bottle of soda.
I cannot figure out how everyone got talked into this. I think it’s just a scam.
I remember our daughter explaining that the water she bought, came from an Artesian well high in the Alps.
I told her that the water was pure and did come from an Artesian well high in the Alps, but that they ran it through a rusty old pipe down to the dock and into an old rusted tanker ship.

I’ll stick with my “well water” and refilling my bottles at the sink.


I hear that in Italy, rotgut is significantly cheaper than water . . .

Perhaps some idiot will top off his radiator with rotgut, because it’s cheaper, and maybe the liquor store is closer than the car parts store


Then it’s the airlines that use N2 for its fire-suppressing tendencies.