SAguirre

I am wondering if anyone here has any idea why some tire stores are not putting regular compressed atmospheric air in.

Yes, this is a new one. I was just at Costco getting the good-old Audi’s tires rotated and balanced and when I came out to pick up the car the valve caps were GREEN! I asked the employee why and he responded saying that the tire now has only Nitrogen in it. I also have a sticker in the windshield saying that I have Nitrogen in the tires.

Now this means that I am theoretically not supposed to just fill the tire with my air pump in case I have to top them off when the temperature drops. But if I have to I will. I asked the employee and he was clueless, hence mounting tires for a living. I don’t want to sound elitists, but that is the way it sometimes is.

It can not be that Costco wants to keep you hooked on them for tire service. Once you buy the tires there you have lifetime rotating, balancing and road hazard. Most Germans laughed at me when I asked if such a thing existed when I bought tires in Germany. So for al of you on the other side of the pond, this is very common at tire places in the US, but not at the actual car dealership.

I have been SCUBA diving for 14 years and I am a certified cave diver and have used many different air mixes to minimize decompression time so this is my theory: If Oxygen is generally about 20% of the atmospheric air (1 bar = 14.7 PSI) and tires have about 30 to 40 PSI (hence approximately 2 atmospheres), then the volume of air in the tire has two partial pressures and has the equivalent of air with 40% Oxygen. If Oxygen is the key fuel in combustion and Nitrogen is inert, then there could be a benefit in having a tire totally rid of Oxygen. I know that the space shuttle definitely does not have simple atmospheric air in its tires.

But when has anyone heard of a car tire exploding due to its Oxygen content?? Also, is the extra safety worth the trouble? Nitrogen is lighter and could leak easier, right? I mean, someone is now going through the trouble of separating the Nitrogen from the atmosphere and then putting it in tanks and then shipping them to the tire centers.

This one stumped me, what do you think?

Steve A.

lig

Nitrogen is supposed to be more resistant to pressure changes due to heat.

Very common in racing/track/auto-x applications.

You can certainly add air without a problem - you just lose some of the benefit of nitrogen filled tires.

SAguirre

What a simple answer! I guess that if it is less sensitive to heat, then it will also maintain pressure in the cold? I think that a simple rule is that if the temp drops 10 degrees F, then the pressure goes down by 1 PSI. So he in Colorado I can easily go from 60 degrees in Longmont to -10 degrees in Vail within 3 hours of driving. A 7 PSI drop. Do you think it will help in this case too? Do you think it is worth it?

Thanks for the answer,

Steve

MB Fanatic

Nitrogen molecules are much larger than those of regular oxygen. This means that the nitrogen will escape from the tire over a longer period of time than oxygen. Also it helps to maintain uniformity in the tire when driving at high speeds since the air will not expand as much since nitrogen is much harder to heat up.

So yes it is worth it and I have Nitrogen in the Pilot Sport A/S right now for a month and the gauge still shows 35 psi on all corners and the install was done by Costco in Southern California.

SAguirre

I shop at Costco quite a bit and it is nice to know that they go this extra mile when it comes to tires (no pun intended). But this is new thing with Costco, I have been getting my Audi's tires serviced there for the last 100,000 miles and this just came up now. It all makes sense, but I did not think that a discount warehouse would do this.

I will see what it will cost to change the MBs tires air to Nitrogen, at least the winter tires.

Thanks for all the info.

Steve

MB Fanatic

I am pretty sure they will. They even rotated the tires in our minivan for free, even though we didnt get the tires from them, and they did fill it up with Nitrogen instead which is always a good thing I guess.

Double Eagle

Another benefit to using nitrogen is the much lower probablility of moisture forming in your tires. Such moisture can freeze in low temperatures and cause erratic balance conditions until tires warm up. All aircraft tires have been filled with "dry nitrogen" for years as a safety measure. Many air compressors do not have moisture traps and you can feel and see the moisture from them at times. Costco is clearly a leader in this arena and my guess is that others will soon be using nitrogen as well.

em2023

Was researching the topic of nitrogen in tires and heres what i came up with.

http://www.tirelast.com/id15.html

a2gtinut

good find.
Almost all/most (better) tire places in Europe use N2 to pump tires.
But if you want to keep tire pressure more stable for racing than you have to use helium.
BTW. Helium is used in F1 and others.

MBZFAN55

These 2 articles will give you the industry perspective on nitrogen inflation. It is going to be very "hot" particularly at high line dealerships. My MB dealer just put it in, and says the response has been great.


http://www.aftermarketbusiness.com/a....jsp?id=136013

http://www.aftermarketbusiness.com/a....jsp?id=101650

HELL ONA HARLEY

Nitrogen in your family sedan......L.O.L.....
Sorry guys, but this is a sales gimmick at best.
Yes, race cars MAY see a slight (and I mean slight) difference, but you in your MB on a public highway will certainly not. Last I checked the atmosphere is made of 78% nitrogen already...

But hey, who am I to say whats right or wrong for you???.... If nitrogen filled tires some how make you feel better then hey.... knock youself out.

SAguirre

Well, the only thing that I can attest to is that now I don't have to worry about pressure fluctuations due to temperature changes. Here, it is totally normal to have a 65-degree day and a –10-degree night when I drive up to the mountains to go skiing. This could be a 7-PSI over or under inflation issue on my tires. I have checked the pressure recently and it seems to be stable no matter what the outside temperature is. I LIKE THAT!

I might be one of a few who can benefit due to these temperature changes, but I do like not worrying about tire pressure anymore when the temperature swings to such extremes.

Steve

pfphipps

Go to here to see what Goodyear Racing says about it:

http://www.racegoodyear.com/about/fast_facts.html

A short summary of what they say:

"Some race tires are inflated with air treated by a special dryer to remove excess moisture, which results in better tire pressure control. While Goodyear's "tire busters" fill all tires at the track with air, many teams will deflate their tires and refill them with nitrogen. Pure nitrogen is "dry air" while regular air can have varying levels of moisture. Some teams also believe nitrogen makes for a more consistent product from tire to tire."

I am using the 80% nitrogen mixture myself. That is plain old air. My $100 Sears compressor has a dryer but even without it, I would not worry much about it.

By the way, how does Costcos suck out all the air, with that nasty oxygen, before they fill the tire with nitrogen? And have you seen the high school dropouts (or at least act like it) they hire in the tire department?

MBZFAN55

You're absolutely correct, but it's the 22% that you have to worry about.

HELL ONA HARLEY

I do agree that when racing proffesonaly on a track at extended high speeds this and many many other variables will make a better race car and better traction stability...As anyone knows, its the combination of many small things that add up to make a great race car or team.... But nitrogen alone will do nothing, especialy for your family sedan...But hey, if I could sell more tires by putting nitrogen in them then hey, who am I to argue with one fantastic marketing genius.

Sorry guys I'm not on the ban wagon this time.... Happy trails.

pa28pilot

I have seen a couple of other posts about this over the past year or so. I am sure it is an inexpensive (though less so than air) way for costco to differentiate themselves.

I am not convinced of the utility for the common man.
The poster who mentioned condensation/ice seems closest to the mark, as science goes.

Aircraft struts are pressurized with nitrogen, primarily to prevent corrosion of the inside strut surfaces due to moisture in ambient air. If costco is claiming that to top off with air will harm the car, they should be prosecuted for fraud. YMMV.

HELL ONA HARLEY

Here's something else to consider..... How long does that precious nitrogen stay in your tires before you have to replenish it???? Race cars change the nitrogen at every race. Case in point.... I'm sure you guys have seen a Helium (pure) filled ballon in your house floating against the ceiling, right????

Well, ponder this for a moment.....Have you noticed after a few days the ballon will start to fall to the ground yet its still filled??? Thats because air will exchage its self even when there is presure in the ballon... As the Helium escapes through the molicules of the ballon the atmosephere (78% nitrogen, 21% oxygen and 1% impurities) will replace it. Nature has a strange way of always trying to restore order.... So how often are you replacing your atmosphere (air) contaminated tires with Nitrogen again.... I would think at least every few days if not sooner to keep them "pure".... This same principale applies to a breathing tube in a submarine....

Just something to think about.........

thearle

Costco has the equipment that uses a chemical process to extract 99.9% nitrogen. It is about $12,000 - their cost!

I was intruiged at first so I did my own test (I encourage you do the same)...

Try running regular air on one side of your vehicle, and the Costco nitrogen on the other side. Set the same pressure on both sides and then drive a few miles on a hot day. Then re-check your tire pressure.

My findings:

Regular air increased by as much as 5 psi.
Costco Nitrogen went up by a mere 1 psi.

I am sold!

BTW - not all Costco employees are what you describe. I know someone who works at the tire center that drives a 2004 SL55 and is just about to finish his college degree from a private school. He said that it's a way for him to learn the real world.

HELL ONA HARLEY

Obviously a Costco stock holder......


Must be nice to have rich parents...And I really don't think he's going to be learning much about the "real world" working at Cosco... This takes a life time of experiences....