Even if nitrogen didn’t change pressure with air temperature, we’re forgetting one important thing. New tires don’t go on the rim and form a vacuum. That tire already has atmospheric air in it when it’s mounted on the rim.
Unless they run a double valve system to purge the regular air while introducing the nitrogen, complete with sensors to tell them when all the regular air has been purged, then you’ve still got oxygen and water vapor in there.
Without cutting and pasting the entire thing, here’s what Tirerack has to say about it.
Overall, inflating tires with nitrogen won’t hurt them and may provide some minimal benefits.
Is it worth it? If you go someplace that provides free nitrogen with new tires, why not? Additionally we’ve seen some service providers offering reasonable prices of about $5 per tire (including periodic adjustments for the life of the tire) to a less reasonable $10 per tire (with additional costs for subsequent pressure adjustments) or more as part of a service contract, which we believe exceeds the value of nitrogen’s benefit.
Rather than pay extra for nitrogen, most drivers would be better off buying an accurate tire pressure gauge and checking and adjusting their tire pressures regularly.
By the way, ok4450, on this last post, how do you find an accurate tire pressure gauge? By brand, checking reviews online for the model, highest price = best, trial & error?
I mean not being knowledgeable, there’s no way to tell its accuracy unless you test the gauge against several other gauges on hand, and have a reference value (from one gauge or knowing what the tire is currently inflated to, etc.).
I once had a faulty gauge and never knew it until used another gauge that gave different & more accurate results. Turns out the faulty gauge seemed to show ok pressure when it was actually underinflated lower pressure on the tire. So I unknowingly had underinflated tires for quite some time.
@texases
Not saying I agree; but, arguably, if the tire pressure stays more consistent, theoretically, then the tires do last longer. If, “you don’t bother checking it regularly. " it works for a lazy customer. So, what’s the big deal. It isn’t like they are trying to sell you something that will actually " kill” you like claiming your SUV can take a corner and not roll over at 90or 105 mph. They are stretching the truth to be sure, to put their kids through school. This is a very noble and capitalistic way of making money.
@shadowfox
I didn’t hear the pressure was more insistent because it doesn’t change with the temp. It doesn’t loose air as rapidly which makes it more consistent. What you say is true…but good grief man, it’s the American way and they aren’t making any claim that is factually wrong, at least in the tire dealers I go to. It is useless to you and I, but so isn’t a bag of Cheetos…and “that stuff kills you slowly”. No one tells you the truth about that ! Especially the food vendor.
For practical purposes, nitrogen and air act the same way. So it doesn’t matter whether you have nitrogen or air in the tire, treat them the same way.
Even the presence of water vapor doesn’t affect the way air reacts. Besides after a bit of time, even liquid water permeates through the tire and the only thing in the tire is gas (some of the gas is water vapor) - and all gases react the same to temperature. It’s called the Ideal Gas Law - and in the range of temperatures we experience as weather, all gases behave vey much like an “ideal” gas.
To the best of my knowledge, the tire inner liner is composed of butyl rubber (or some form of it, some being better than others). Butyl rubber has exceptional resistance to gas permeation. Here is an article that addresses some of the areas covered in this thread, especially the difference in gas permeability between O2, N2 and atmospheric air. In short, N2 and air are bascially identical, there is no advantage at all.
Also, the gas permeability of this liner is so small that these ideas there are great exchanges or loss going on are ridiculous to me. I have cars sitting on tires for >5 years with no attention that are still as full as the day they were parked (when checked under similar conditions). Leaks AROUND the tire or through the rim/stem are far more likely than significant volumes of gas getting past the inner liner of the tire.
@texases
Are you saying then, that nitrogen does not migrate through rubber at a slower rate then O2 ?
Cause if the answer is yes, then technically, you are incorrect, and notrogen pressure does stay more consisten. Now the question in my mind is…is it significant enough to matter and is it practical for a regular car user…"a resounding no for that.
I like this explanation…and I’m sticking to it ! http://www.pedrosgarage.com/Site_5/Nitrogen_or_Air.html
@dagosa - here’s a great example of how a marketer takes a small difference and uses it in a VERY misleading way. The actual tests of the difference in tire pressure over time I’ve seen show about a 1 psi difference over a year. That is meaningless, the changes from season to season are much greater, and folks need to be checking and adjusting their tires at least seasonally, if not more often.
So technically, it might be true (although I put ZERO faith in a website of a company selling nitrogen). But even if true, it’s been demonstrated to be meaningless in the real world.
How about CR http://www.consumerreports.org/cro/news/2007/10/nitrogen-in-tires-q-a/index.htm
I agree it is meaningless in the real world. But I repeat, there is no lying, just good old capitalism deception…and I applaud their efforts to try and bilk us out of our hard earned dollar. A lot of stuff. Is sold to us that we don’t need ! This is one.
"Consumer Reports wanted to find out if nitrogen is worth the price, so we purchased a Nitrogen Inflation System and checked out how well the inflation held up over a one year period. We evaluated pairs of 31 tire models of H- and V-speed rated, all-season tires used in our tread wear test from 2006. We filled one tire per model with air and the other with nitrogen. The test was quite simple: fill and set the inflation pressure at room temperature to 30 psi (pounds per square inch); set the tire outdoors for one year; and then recheck the inflation pressure at room temperature after a one year period.
The tires were filled and deflated three times with nitrogen to purge the air out of the tire cavity. We also used an oxygen analyzer to be sure we had 95-percent nitrogen purity in the tire–the claimed purity limit of our nitrogen system, which generates nitrogen gas from ambient air.
The test started on September 20, 2006 and the final measurements were taken on September 20, 2007. The results show nitrogen does reduce pressure loss over time, but the reduction is only a 1.3 psi difference from air-filled tires. The average loss of air-filled tires was just 3.5 psi from the initial 30 pressure setting. Nitrogen-filled tires lost an average of 2.2 psi from the initial 30 psi setting. More important, all tires lost air pressure regardless of the inflation medium, so consumers should check their tires’ air pressure routinely. No evaluation was done to assess the aging claim.
Bottom line: Overall, consumers can use nitrogen and might enjoy the slight improvement in air retention provided, but it’s not a substitute for regular inflation checks.
So, I will conclude that if Ralph Nader were allowed to put his finger print on this discussion, he would say " you want to advertise that nitrogen retards pressure lost ? Go ahead ! But include your test results so the consumer can make up his own mind if one pound a year loss at most is worth the $$$$$. "
That way…everyone is happy cause the tire shops can put it in real small print…
Here are the benefits listed at the first page of the nitrogen web site, and my [comment]:
Increased fuel economy [LIE #1: they base this on somebody keeping their tires inflated with nitrogen, vs. not checking their tires. 100% bogus]
Increased tire life [LIE #2: see above]
Improved handling and traction [LIE #3; see above]
Better for the environment [LIE #4: see above]
ALL their claimed benefits solely result from people maintaining their tire pressure better with nitrogen, which has nothing to do with nitrogen. The negligible difference in pressure reduction is meaningless when it comes to maintaining proper pressure.
We could go round and round on this. You are arguing practicality, which I do not disagree with; while I simply state that what they say is all technically true and not a lie. Ask me if I put nitrogen in my tires ? Don’t you think it’s a bigger scam when sellers actually lie to make a profit on real lies. Having nitrogen in your tires hurts no one except the gullible. I would like to see more research and distain over food labeling then this insignificant example of capitalism at it’s finest where no one is getting hurt by it.
I recently read a very interesting book. It’s called “Engines of change” by Paul Ingrassia
In that book, he spends some time on Ralph Nader. It mentions that he also tried to go after VW. In his eyes, the Beetle was also unsafe, because of its midengine layout.
It turns out that he was unsuccessul. VW beat his ass down
"Why did you bring up Ralph Nader"
It worked…it got a rise out of someone. Besides, I don’t think the head of a large financial corporation is going to have an independent reading on the “worth” of Ralph Nader. There is as much distortion in his writings on Ralph Nader as there is by tire companies on the advantages of nitrogen. Just ask @texases how much there is there.
To cite just one example, he cites an “unnamed expert” AT CHRYSLER regarding the safety liabilities of rear-engined cars. Now, Chrysler had ZERO rear-engined cars, but had TWO COMPETITORS that did.
So, by including this “expert opinion” without pointing out the obvious bias, we can conclude that Nader is:
a. Too stupid to notice the confilct of interest,
b. Too ethically compromised to care, or
c. Both a. and b.