Nitrogen Filled Tires a Scam?

Nitrogen Filled Tires a Scam?

The claims are this:

1. Nitrogen-filled tires maintain proper pressure longer
2. The rubber of nitrogen-filled tires last longer
3. Nitrogen is less volatile than oxygen and thus safer in a fiery crash
4. Cars with Nitrogen-filled tires get better gas mileage
5. Cars with Nitrogen-filled tires are better for the environment

The last two claims are dependent upon the expectation that the tires filled with nitrogen are actually at properly inflated pressure more consistently. So let’s set them aside and focus on the first three points.
1. Do nitrogen-filled tires maintain proper pressure longer? The premise for this claim is that nitrogen is a larger molecule than oxygen. It is. Only slightly. But let’s not omit the fact that we’re talking about molecules here and not just the element. Oxygen and nitrogen are both diatomic molecules. Nitrogen actually has less mass than oxygen, so Graham’s Law dictates that it diffuses a bit faster than oxygen. However, since the actual size of the oxygen molecule (O2) is a bit larger than that of a nitrogen molecule (N2), this only applies if the opening from which the molecules are effusing from is large enough to permit the largest of the two. In such cases, N2 will diffuse faster.
The question, then, becomes, are the pores in rubber (assuming there are such pores) smaller than the N2 molecule but larger than the O2 molecule? I don’t know the answer to this. Nor could I find any literature in the few minutes I searched, but if anyone has a citation to an independent (i.e. non Nitrogen Tire industry) study or bit of research, I’m interested. Without digging out my old chemistry textbook, I’m willing to tentatively accept Wiki Answers on the sizes of N2 and O2 molecules: N2 is roughly 300 picometers while O2 is slightly smaller at 292 picometers. I’m open to revising these figures if someone cites a more reliable source, but I can’t imagine that there’d be any reason for the link to be more than slightly wrong.
2. Does rubber oxidize faster when exposed to oxygen rather than pure nitrogen? I’d expect so. The real questions are: a) how to you keep oxygen on the outside of your tires from causing oxidation?, and b) does it really matter to me since every single tire I’ve ever replaced was because of worn tread and not oxidation?
3. Why do I give a **** whether or not the oxygen in my tires will fuel the fire of my fiery crash? If the explosion is powerful enough to consume the oxygen in the surrounding air leaving only my tires as reserve fuel, I suspect I’m going to be a crispy critter anyway.
As for 4. and 5., I’m not that arsed for time that I can’t continue my routine of checking my tire pressure every 3,000 miles when I change my oil. In fact, nearly every time I’ve ever checked my tires at 3k, they’ve either been dead on for the proper psi or just a pound or two off. Whenever I’ve had to fill more than that, it’s been either because of a faulty valve or a nail in the tire itself. I suspect that the resulting points of egress in a faulty valve or pucture would create holes large enough for either O2 or N2 to escape through effusion. So, in that case, Graham’s Law would be in effect and N2 would escape faster than O2.
The bottom line: if nitrogen becomes a free option, easily obtainable (i.e. cheaper and easier than the $5.00 Walmart compressor that I plug into my cigarette lighter), I’ll use it since there’s a very slight chance I won’t need to top off my tire pressure as often. But, as long as I have to pay for it or even just drive to the dealer for it, I call bull****!
Nitrofill is a scam. Nitrogen-filled tires for general consumers is a scam.

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Most tires are filled with compressed air, which when dry consists of about 78 percent nitrogen, 21 percent oxygen, and 1 percent other gases by volume. Water vapor (humidity) can make up as much as 5 percent of the volume of air under worst-case conditions. Filling your tires with nitrogen mainly does two things: it eliminates moisture, and it replaces skinny oxygen molecules with fat nitrogen molecules, reducing the rate at which compressed gas diffuses through porous tire walls. That means, theoretically at least, that a tire filled with nitrogen retains optimal pressure longer, leading to more uniform tire wear and better gas mileage. The commonly quoted figure is that tires inflated to 32 psi get 3 percent better mileage than at 24 psi.
Does nitrogen make any practical difference? You couldn't prove it by me. I found no scientific tests showing that nitrogen-filled tires stayed inflated longer than average under normal conditions. A car-buff buddy was sure it worked but conceded he had only anecdotal evidence that it did.
As for moisture, changes in humidity affect tire performance two ways. First, the density of humid air fluctuates more with temperature than that of dry air, so removing humidity can keep your tire pressure more consistent, especially when the temperature climbs over 100 degrees Fahrenheit. That may be a legitimate concern in Formula One racing, but it's not much of an issue if you're just tooling around town.
Humidity can also be a factor in wheel maintenance - since pure nitrogen doesn't have moisture in it, supposedly your wheels won't rust as quickly, which could lead to improved wheel performance and air sealing. The question is, how big a problem is wheel rust these days? According to a few tire and wheel shops we contacted, not very. Seriously rusted wheels are uncommon in typical steel-wheeled cars, and many high-performance cars have alloy wheels that don't rust at all. One exception is work vehicles such as dump trucks, which are exposed to a much harsher environment.
Another claim I've seen is that since nitrogen is slightly lighter than air, you'll save weight and get better performance. However, we're talking about a weight difference of less than 4 percent of the gas in the tire - in other words, a difference of less than an ounce for most vehicles. A possibly more realistic benefit is that nitrogen is largely inert chemically at low (i.e., normal) temperatures, so it won't attack the rubber in your tires like oxygen does. Oxygen attack is something both the National Highway Traffic Safety Administration and Ford Research have studied, and can be a problem for tires used for a long time or in rough conditions.
More important, nitrogen doesn't support combustion, which is one reason aircraft and the space shuttle use nitrogen in their tires. The wisdom of this precaution was brought home by the crash of Mexicana Airlines flight 940 on March 31, 1986. Shortly after the Boeing 727 took off from Mexico City en route to Puerto Vallarta, an overheated landing-gear brake caused a tire improperly filled with air instead of nitrogen to overheat as well and explode, rupturing fuel and hydraulic lines. The ensuing fire and crash killed 167 passengers and crew. However, unless your driving habits are of the X-treme variety, the chances of your tires catching fire anytime soon are slim.
Overall, filling up with nitrogen won't hurt and may provide some minimal benefit. Is it worth it? If you go to some place like Costco that does it for free with new tires, sure, why not? Elsewhere, though, I've seen prices quoted as high as $10 per tire, which is way more than I'd pay. Rather than shell out for nitrogen, you'd be better off just checking and adjusting your tire pressure regularly, something the NHTSA says less than 60 percent of U.S. motorists actually do.

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Pumped up by nitrogen


Experts say use of gas in tires not worth the cost



haven’t thought about nitrogen - letter N on your periodic table - since high school chemistry class. But this summer my dad told me how his nitrogen-filled tires made for a smoother ride. Then my local Shell station started advertising “nitrogen-enriched’’ gasoline for a cleaner engine. What automotive miracle, I wonder, will nitrogen produce next?
With school back in session, this week we present a chemistry lesson for car owners. How long should the Freon in my car’s air conditioner last? Are modern cars impervious to salt corrosion? Should I splurge on nitrogen for my tires, or will old-fashioned air suffice?
Q: Is it better to fill your tires with nitrogen as opposed to air? The claims are convincing: Nitrogen gas doesn’t leak through rubber the way air does, so you can go months without losing tire pressure. In turn that means better fuel economy and smoother rides.

With less leakage, your tires will even last longer, says NitroFill, which outfits car dealerships across the country with nitrogen gas pumps.

But nitrogen will cost you: $39.99 to fill up your car’s tires, $49.99 for trucks or SUVs, according to a NitroFill dealer I phoned. Is the added cost worth it?

I posed the question to John Heywood, director of MIT’s Sloan Automotive Laboratory.

“You might want to point out that air is about 80 percent nitrogen. So basically, why would nitrogen be that different from air?’’ Heywood asked. “My own experience is that unless you damage the tire or there’s a leak around the rim of the tire they hold their pressure pretty well. And increasingly, new cars have pressure gauges. So my advice would be don’t bother, don’t waste your money, air is free.’’

I called Michelin next, and the tire giant said the same thing.

“All of our tires are designed to deliver their expected performance when inflated with air,’’ read a company statement.

That’s not to say that nitrogen is a scam. Michelin agrees that nitrogen leaks more slowly than air, and that it “may be advisable’’ to use straight nitrogen in racing and airplane tires because of the special stresses they require.

But it’s not worth filling up your car’s tire with nitrogen, Michelin says, because there are plenty of places where tires can spring leaks (valves, rim interface) regardless of what is inside.

“There is no substitution for proper maintenance and regular [at least monthly] pressure checks,’’ said Michelin spokesperson Lynn Mann.

My dad was unfazed by my research. He said his Chevy Tahoe has better braking ability, turns better on corners, and rides more smoothly since he pumped up with nitrogen. “Whatever they want to say, I found a difference,’’ he said.

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we have both at the shop and we couldnt tell the difference

the only thing is if the tire loses air how many gas stations have nitrogen ?

we would say its just a money grab

also if your car is on fire ... do you care is the tires have air or nitrogen when your standing 500ft back ? ... dont mind the 1/2 empty gas tank

lol

i have used nitrogen for years on my racecar tires and can tell you for racing it does make a huge difference. to properly get a car to handle you need to maintain your tire size (stagger) on the racetrack. with nitrogen we have been able to do that consistently. now im not sure about street tires as i have not tried in those yet but as far as racing all claims are correct

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Testing: Sonysat DCR5500, pansat 9000hd, sv4k, sv360premier, pansat 2700a, coolsat 6000 and satopia ST1100-UT

We tried nitrogen in big truck tires and the only thing we found was your tires run alittle cooler,but not worth the expence of filling with nitrogen. Didnt notice much differents in handeling either. Id say its an expence we could do without.

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Remember today is the first day of the rest of your life,make the best of it!




Testing Visionsat IV 200,Viewsat extreme 2000,and Satopia

as for racing ... yes it is the diffrance between first and last

as for street ... if your racing to get a burger ... maybe but not cost efective

LOL yea i cant see where it would make that much difference for the street actually. besides anyone who knows someone with the telephone company or go to your local airgas supplier you can buy a bottle of the stuff and do it yourself and is much much cheaper also with all the extra you could sell some to your friends

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Testing: Sonysat DCR5500, pansat 9000hd, sv4k, sv360premier, pansat 2700a, coolsat 6000 and satopia ST1100-UT