Nitrogen in Tires

[AnnapolisAirhead]

Has anyone used nitrogen instead of air in their tires? I know its used in cars, just curious about bikes.

The notion goes that it neither expands nor contracts with varying temperatures like air does. I'm also wondering about the effects of water in tires over time from one air compressor to the next, especially as it may relate to tank slappers. Would the use of nitrogen also help?

[LOSTBOY]

The notion is just silly. Nitrogen expands and contracts with temperature changes, just as "regular air" does. After all, our atmospere consists of 78% nitrogen. The only advantage to using "pure" nitrogen is that it should have no moisture in it. Out of the thousands of tires I've changed over the years, I doubt that I've found moisture in ten of them.

The funniest part about this push to sell nitrogen-and that's what this is really about, another small charge to hit you with-is that the nitrogen machines only give you something like 98% nitrogen.

Another claim is that nitrogen filled tires run cooler. The only way that's going to happen is through greater air pressure or reduced friction at the tread.

[PGlaves]

Has anyone used nitrogen instead of air in their tires? I know its used in cars, just curious about bikes.

The notion goes that it neither expands nor contracts with varying temperatures like air does. I'm also wondering about the effects of water in tires over time from one air compressor to the next, especially as it may relate to tank slappers. Would the use of nitrogen also help?

Nitrogen is a gas. It expands and contracts, as do all gasses. I'm not a chemist so can't say whether there is a significant difference in the expansion of a gas that is 99% nitrogen or one that is 82% nitrogen (air). I don't think so, but ....

Probably the two big differences: some vendors install dehydrated nitrogen - moisture removed. The other big difference is the amount of $$$ left in your wallet.

If I planned to run on the salt flats, or run a race bike on a big oval like Daytona, where tire heating might vaporize water - maybe. On an Airhead you would never know the difference.

[35634]

google "nitrogen inflation" There probably is some validity in using it. Mainly
nitrogen escapes at a slower rate than other gasses, more consistent pressure
due to reduced water vapor, and oxygen, vapor, and other gasses not reacting with the
tire insides and rim. NASCAR, Airlines and the military use it. Also, 93-96%
pure seems to be the limit for diminishing returns. I'd try it if someone offered
for free, otherwise regular air works for me.

[orbitangel]

Has anyone used nitrogen instead of air in their tires? I know its used in cars, just curious about bikes.

Check this link: http://www.getnitrogen.org/why/index.php

I have been putting dry nitrogen into the tires of the jets I work on (ALL the airplane tires & struts, in fact) for so long I hardly think about it. Naturally, I use it in my BMW's tires as well. I like it.

Anyone who prefers wet, oily "gas station air" is welcome to it.

"Quality is what you like." (Pirsig)

[AnnapolisAirhead]

whoops, I really wasn't trying to start another thread without end, just trying to find someone who's actually had experience with it rather than just opinion.

I find as much marketing crap for it as I do against it. I guess until there is a truth meter on websites, any idiot can dress up a page as an authoritative one. There's no replacement for experience, but like the 'do I use tubes with snowflakes or not' debate, I'm thinking it comes down to personal preference--not even science this time.

Thanks for the input guys.

[yrfuneralmytrial]

No experience with it whatsoever but the when I was first shopping for a Prius (hey, 46mpg ) the first sales guy tried to put the deal over the top by promising me free nitrogen for the life of the car. I said "F.U. buddy" and kicked his ass on the spot. Ninja style.

[moondog]

Required use on 99% of aircraft in tires, landing gear struts, and emergency braking systems. Required because it is non-flammable and moisture free. I would use it on my bike but I don't have any handy so I use my compressor.

[DennisDarrow]

Golly I love the modern marvels combined with marketing and conspicuous consumption.

As I sit here drinkin my morning coffee made with water that comes from that spring bubblin under my hill I wonder how in the world I missed another opportunity to market a product that is just there. I missed out on the NEED for bottled water, now I missed out on air.

Shucks..........Dennis

[rocketman]

Five minutes looking around shows that its a scam for the general consumer..more than you ever wanted to know...


http://www.straightdope.com/columns/...instead-of-air
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and from another site

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 letÔÇÖs 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 letÔÇÖs not omit the fact that weÔÇÖre talking about molecules here and not just the element. Oxygen and nitrogen are both diatomic molecules. Nitrogen actually has less mass than oxygen, so GrahamÔÇÖs 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 donÔÇÖt 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, IÔÇÖm interested. Without digging out my old chemistry textbook, IÔÇÖm 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. IÔÇÖm open to revising these figures if someone cites a more reliable source, but I canÔÇÖt imagine that thereÔÇÖd 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? IÔÇÖd 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 IÔÇÖve ever replaced was because of worn tread and not oxidation?

3. Why do I give a sh*t 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 IÔÇÖm going to be a crispy critter anyway.

As for 4. and 5., IÔÇÖm not that arsed for time that I canÔÇÖt continue my routine of checking my tire pressure every 3,000 miles when I change my oil. In fact, nearly every time IÔÇÖve ever checked my tires at 3k, theyÔÇÖve either been dead on for the proper psi or just a pound or two off. Whenever IÔÇÖve had to fill more than that, itÔÇÖs 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, GrahamÔÇÖs 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), IÔÇÖll use it since thereÔÇÖs a very slight chance I wonÔÇÖt 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 bullsh*t!
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Nitrofill is a scam. Nitrogen-filled tires for general consumers is a scam.
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The Rubber Manufacturers Association has also issued this statement:

Applications such as aircraft, mining, and commercial/heavy use utilize nitrogen to help reduce the risk of internal combustion (fire) if the brake/rim/wheel components overheat. Also, dry nitrogen is used in professional racing to help reduce variation in inflation pressures (caused by moisture) where even small differences in pressure can affect vehicle handling at the extreme limits of performance.

For normal tire service applications, nitrogen inflation is not required. However, nitrogen inflation is permissible as its properties may contribute to minor reductions in inflation pressure loss. Nevertheless, several other sources of pressure leaks, such as punctures, tire/rim interface (bead), valve, valve/rim interface, and the wheel, may negate the benefit of nitrogen.

If the tire inflation pressure is below the pressure specified on the vehicle placard, the tire must be re-inflated ÔÇô whether with air or nitrogen ÔÇô to the proper inflation pressure.

RMA warns that depending on nitrogen alone to reduce the requirements for inflation maintenance may, in fact, lead to under inflated operation, which may result in premature tire failure.

ÔÇ£With the right amount of inflation pressure, you will achieve optimum tire performance,ÔÇØ RMA wrote. ÔÇ£This means your tires will wear longer, save fuel and help prevent accidents.ÔÇØ

And above all, the RMA bulletin strongly reminded motorists to check tire pressure at least once a month when tires are cold and to use the vehicle manufacturerÔÇÖs recommended inflation pressure.

ÔÇ£Whether inflated by air or nitrogen, regular inflation pressure maintenance remains critical and necessary,ÔÇØ RMA wrote. ÔÇ£Use of nitrogen alone is not a replacement for regular inflation pressure maintenance.ÔÇØ

The RMA bulletin notes that nitrogen is an inert (non-flammable) gas ÔÇô basically, nothing more than dry air with oxygen removed (air contains about 78% nitrogen). Because of its inert properties, nitrogen is often used in highly specialized service applications and/or demanding environments.
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and another site ran a test of O2 and N2 filled tires and found that O2 lost pressure at 3.5% while N2 lost it at 2.5% OVER A YEAR! Wow, that sold me!


RM

[beemerguru]

If you're in the Bay area and go to Road Rider in San Jose, they have been using the gas for years. You'll find 30-50 bikes there every day on the weekends and 15-20 every day during the week getting new rubber. Never heard a complaint...only compliments.

[troutluck]

I hear unicorn farts work the best for inflational rotationary coefficient conundrums.

[orbitangel]

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Nitrofill is a scam. Nitrogen-filled tires for general consumers is a scam.
-------------------------

RM

Nitrogen (DRY nitrogen) IS what it IS (a purified, inert gas.)

Clever marketing to people who may or may not want it might be a scam.

I use dry nitrogen because it is "better" than air and costs me nothing.
But I'm not anal about it an will use air from anywhere if I need to.

While the benefits from using it may be debatable, NOBODY can convince me that there is anything WRONG with using dry nitrogen to fill my tires.

We can all agree that the tires need to be inflated with SOMETHING.
If something better comes along I will use it. No sales pitch from me. Use what you like.

[orbitangel]

... There's no replacement for experience, but like the 'do I use tubes with snowflakes or not' debate, I'm thinking it comes down to personal preference--not even science this time.

Thanks for the input guys.

Hey, Annapolis Airhead: I happen to have some experience in this area you may or may not be interested in.

In my case it was Lester wheels (I have ridden at least as far on snowflake wheels and the information is equally valid for either wheel type.)

Here is the condensed version: I hit a square-edged, NINE INCH DEEP pothole dead-on at 105 MPH in twilight conditions. I never saw it. The impact was so violent it tore the bars (R100RS) right out of my hands. The impact bent both Lesters, cracked the rear one on both sides as well, bent the rear axle and rear subframe.

My old Conti combo (RB2/K112) (this was thirty years ago) TUBE TYPE tires remained inflated. BOTH tires, had they been tubeless, would have gone flat INSTANTLY. If they had been tubeless tires I would have been killed.

A violent spill at 105 MPH would have been bad enough but I had just passed two fully-loaded wheat trucks which were right behind me doing 80 MPH.

EVERYBODY rides on tubeless tires nowadays. I do NOT! Those tubes saved my butt once and I won't soon forget it.

When it was all said and done I rode 40 miles home on two VERY lumpy wheels, not happy but alive.

The dealer threw away two Lester wheels, two tires and tubes, one swingarm, one rear axle, and one buckled subframe. It could have been much, much worse.

[535IS]

Nitrogen (DRY nitrogen) IS what it IS (a purified, inert gas.)

Nitrogen is far from inert! [Ask Timothy McVeigh.] In pure form, it is nonflammable and that's its major, if not only advantage, in some tire inflation applications.

Clever marketing to people who may or may not want it might be a scam.

Clever is one thing. Wild exaggeration in the interest of paying off a $6000 nitrogen generating machine you were a fool to buy is another.

Water in air is the main disadvantage to using air, but it is a simple matter to use a dryer on any compressor line. Spray painters do it all the time. This only really matters if your internal tire temperatures get hot enough to boil any liquid water. Otherwise, water vapor behaves the same as any other gas.

This brings us to the gas laws. As someone who was a chemist and who has taught them, I can assure you that the gas laws are UNIVERSAL laws. That is, they apply to any gas; nitrogen, oxygen, and even gaseous water. PV=nRT is all you need to know to do any of the calculations about gases.

As for the molecular size, it is pretty clear that, if escaping oxygen were a real issue, we would all be riding around on passive nitrogen generators. Think about it. We put in 78% nitrogen and 20% oxygen. The oxygen escapes, leaving behind 78% of your original pressure which you top up with another 78%/20% mixture. That gives you 95% nitrogen right there. That pesky oxygen gets out again and you refill with plain old air to bring the nitrogen content up to over 99% pure nitrogen. It's that simple, folks! Yeah; right.

There are rubber membranes through which some gases can escape. We all know how a rubber helium balloon goes dead overnight. That's because a helium atom (He is inert and as such, cannot be diatomic.) is a lot smaller than other molecules and it does escape from the balloon. But there's a reason we consider our tires to be airtight and that's because they are. The balloon is as thin as possible, which could mean as little as one layer of polymer in some places. Your tires are thousands of layers thick, making escaping gas a non-issue. You could fill your tires with helium and it would still take a significant leak to let it out any faster than oxygen would permeate its way out.

I use dry nitrogen because it is "better" than air and costs me nothing.

While the benefits from using it may be debatable, NOBODY can convince me that there is anything WRONG with using dry nitrogen to fill my tires.

As long as it costs you nothing, that's fine. It truly does no harm, but it also provides no real advantages to air for street motorcycling or driving. It certainly isn't worth paying for.