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BS: Nitrogen in your Car Tires? Bull Or Not

13 Nov 06 - 02:26 PM (#1884866)
Subject: BS: Nitrogen in your Car Tires? Bull Or Not
From: Clinton Hammond

Some folks say it gets you better gas mileage

Other folks say if you check your tire pressure with any kind of regularity, you get exactly the same benefit, but save your 30-50 bucks...

Opinions?


13 Nov 06 - 02:28 PM (#1884867)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: jeffp

This thread has a lot of opinions.


13 Nov 06 - 03:55 PM (#1884931)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: Peace

"I think there are 2 advantages to using nitrogen as an inflation medium.

Nitogen has a larger molecule than some of the elements in air so the gradual air loss is lower.

Nitrogen doesn't have oxygen, so oxygen degradation is lessened.

Personally, I don't think the advantages are worth the price for normal usage. Maybe for cars in a museum or for racing.

I think the reason nitrogen is being marketed is that many people have heard that racers use nitrogen. Well, that's true, but the reason they do is that they don't carry an air compressor to their pit to power their impact wrenches - they use a nitrogen bottle - so they use this to inflate their tires. Plus many racers don't regularly clean out their air storage tank and water gets into the lines and then into the tires. When that happens the pressure buildup is erratic and unpredictable, hence the myth that nitrogen is better."

Found that on the www and its the best cut-to-the-chase remark I have seen on it.


13 Nov 06 - 04:24 PM (#1884949)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: pdq

Even if the tank used to inflate the tire contained 100% Nitrogen, it would be near impossible to fill a tire to the 100% level. The tire would need to be completely evacuated first. Just letting the air out and re-filling with Nitrogen might be 90% effective (or better) but not completely. You will still some oxygen as well as trapped water vapor.


13 Nov 06 - 05:08 PM (#1884995)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: Clinton Hammond

" Nitogen has a larger molecule than some of the elements in air so the gradual air loss is lower."

Ya... according to just about every 'reputable' source I can find (Those being the ones with way less 'wooo' factor than the rest) that theory is a load....


13 Nov 06 - 05:23 PM (#1885011)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

Nitrogen is used in aircraft tires and pneumatic struts because it's necessary to have "very dry" gas at altitude. You can buy a bottle of nitrogen with certified and confirmable moisture content. If you use air you generally have to compress it yourself, condense out the gross moisture, filter the bugs and beetles out, centrifuge out the main part of the remaining moistures and usually run it through an absorber to get the rest of the moisture. Complicated and costly.

Nitrogen is cheaper there, and much more convenient.

Racers use bottled nitrogen largely for the same reasons - because it's much more convenient than dragging a compressor around and more consistent in quality.

Additional "benefits" claimed by either of the above are "mostly mythical."

For the average user, maintaining proper tire pressures is vastly more important than what gas is used, and air is a lot cheaper and much more convenient. You drive up to somebody else's pump and adjust on a regular basis. Consistent maintenance will do a lot more for you than "cheap tricks."

Letting your "installer" fill your tires with nitrogen won't eliminate the need to check them regularly and won't reduce the leakage or changes in pressure due to seasonal temperature changes that result in the need to "add air." The "reduced oxidation" touted by some is immaterial for most users, since the most common deterioration is "sidewall rot" from the outside in.

(Especially with newer tires, and with lighter vehicles, the sidewalls typically rot to unsafe condition well before the tread wears out. Keep it in mind when checking them.)

For most users, nitrogen filled tires ARE BULLSHIT.

One marginally possible use for them might be in an area where very cold winters, with large and sudden seasonal swings in temperature, and very high summer humidity, might cause some "startup thump" due to freezing of even small amounts of moisture. Humid air pumped in during the summer can have quite a bit of moisture that rarely will condense to significant amounts when the temperature drops. This might be a problem if you regularly commute between Panama City and Nome, but then you'll need to carry your own nitrogen bottle for enroute adjustments.

If you "seasonally adjust" by adding air compressed during the season at hand when the weather cools, the air you put in will usually be dry enough due to condensation in the storage tank (unless the tank is indoors and draws it's intake from the sauna at your fillup station) to take care of it. The effect is usually less than the "cold set" of the rubber itself, and it usually goes away after a short drive anyway, so most people needn't worry about it.

In the US, automakers generally recommend lower pressures than the tire "rated pressure" in order to provide a "smoother ride." For most vehicles you can safely check the rated pressure stamped on the side of the tire and inflate to that value. A higher pressure, within the limits of the tire construction, generally will give a little better fuel economy and sometimes better tread wear. A very few vehicles, particularly the high cg "UTEs," are a bit finicky about having exactly the pressure specified by the vehicle manufacturer to get "normal handling." Even for these rare birds, underinflation is much more dangerous than overinflation. Higher inflation pressures, up to the tire rating, may be needed to realize the "maximum gross weight" limits stamped on your door pillar, so investigate if you usually carry a lot of junk stuff around.

For most of us, nitrogen is spelled M.A.R.K.E.T.I.N.G. - because it's something extra they can "offer" to get a bit more of your money, and it's easy to spout "anectdotal proof" that the gullible among us really need it.

John


13 Nov 06 - 05:33 PM (#1885023)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: catspaw49

As I posted in the other thread:

A couple of advantages to Nitrogen but none that would significantly improve anyone's passenger tire performance.......The nitrogen is pure and free of any moisture content which reduces oxidation and the resulting deterioration but more to the point, it reduces the rate of heat build-up and makes the heat building far more predictable. This has no real effect on YOUR car but it does in racing. F1, Indycars, and NASCAR have used nitrogen for years though for just that reason.

Keeping your tires properly inflated, rotated, and balanced with your car correstly aligned will do FAR more to increase the life of your tires and your fuel mileage.

Spaw (ASE Master Certified since 1973)


13 Nov 06 - 07:57 PM (#1885136)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: The Fooles Troupe

JiK

in addition to "You drive up to somebody else's pump and adjust on a regular basis."

It's best if you carry your OWN gauge - even a fairly cheap and nasty one.

At least then, once you have figured out exactly what number on your gauge means correct pressure for wear and ride, you can be confident that you are getting consistent inflation, as many gauges lying around at service stations regularly go out of accuracy due to rough handling, etc.


13 Nov 06 - 09:19 PM (#1885187)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

It's so rare here for the air hose at the service stations to have a pressure indicator of any kind that I neglected to mention that for consistency each car should have its own good quality gauge.

Total agreement on using your own, especially when you get home and check after having new wheels mounted or otherwise serviced "professionally." The gauges used by many service shops are so far off that you'll probably want to adjust things (although I've identifed a couple that are reasonably reliable).

Really good gauges are pretty cheap now, so it's not too necessary to use a "nasty" one. Good digital ones can be had for less than a cup of Starbucks. They should be tossed and replaced when the seal rubber hardens enough to make them "fussy" in use; but of course I've got a fistful that are too good to throw away just yet. I do the replace - just haven't had the heart to do the toss. Some of the old ones, still usable and accurate, have to be at least 50 years old.

John


13 Nov 06 - 09:45 PM (#1885201)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: robomatic

I use a mixture in my tires which is 78% nitrogen. Pretty happy with it.


13 Nov 06 - 10:19 PM (#1885211)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: bobad

" Nitogen has a larger molecule than some of the elements in air so the gradual air loss is lower."

Not trying to be pedantic but just FYI.

Nitrogen (N) is an element (atom) of an atomic weight of 14 and constitutes 78% of our atmosphere.

Oxygen (O) is an element (atom) of an atomic weight of 16 (therefore larger than N ) and constitutes 21% of our atmosphere.

A molecule is made up of two or more atoms.

A property of N is that it is relatively inert ie. does not readily react (combine) with other atoms to form molecules, unlike O which is relatively reactive and can, theoretically, combine with other atoms in the tire to form compounds that are undesirable. I say theoretically because for all intents and purposes this would be negligible in regards to performance, but in the rarified field of auto racing anything that is perceived as providing an edge will be utilized.


13 Nov 06 - 11:55 PM (#1885260)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: catspaw49

John.....Some of the bigger ripoffs are in the digital variety now. Stick with Bridgeport or Superex pencils and a couple of Milton and Accutire dial types for best repeatability/accuracy/reliability etc,

Spaw


14 Nov 06 - 12:29 AM (#1885270)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

While it's easy to reach conclusions based on simple "properties" of chemical substances, it becomes much harder to defend the conclusions against detailed and rigorous probing.

While Nitrogen is "less reactive" than Oxygen in many cases, Nitrogen does react with many other things under conditions (e.g. heat, pressure, and flow) that may well be present in something like an automobile tire.

Reaction products of Oxygen with Hydrogen, Carbon, and perhaps even Sulphur that may be part of the tire carcass are largely neutral (like rust), while reactions of Nitrogen with the same elements quite often can have strong acid/base properties. The tire rubber contains hydrocarbon chain molecules from which, with Nitrogen, NH3 (ammonia) may be produced.

Even if pure Nitrogen is used for an initial fill, the rubber is at least slightly permeable to both Nitrogen and Oxygen and the polymerized rubber itself most likely contains Oxygen, so HNO3 (nitric acid) could easily be formed. Add in the bit of Sulphur and one has a broad range of exceedingly nasty reaction products, containing various assemblages just of N, O, C, and S. (Most tire rubbers contain fairly large amounts of "carbon black" used both for color and for wear resistance, so there's no shortage of "essentially free" carbon to complete the nasties if the polymerized HC aren't enough.)

(I've omitted mentioning H2SO4 since it doesn't suit my argument. :>)

I'm not proposing that all this bad stuff happens; but I'll suggest that the simple arguments usually applied in this case are inadequate to be convincing without additional more rigorous studies that have not been done. (Or that at least are apparently not known to those doing the arguing.)

People have proposed filling tires with Helium, using most of the same arguments as for "pure Nitrogen." That one's pretty easy to deal with, since Helium passes through most rubber about like pouring water through a sock. In an enourmous gas bag like the Goodyear blimp you can get enough containment for useful performance due to the low surface to volume ratio, but you'd probably(?) never finish a race with useful pressure in ordinary tires using helium. (It seeps through most glass.)

To get the benefits claimed for Nitrogen, perhaps filling the tires with Argon would actually be better. I'm sure it's been tried; but I haven't seen the report(s).

The main benefit of using Nitrogen in racing is consistency and convenience. Many people believe in additional benefits, but for the most part those remain questionable when subjected to real examination. Most of the other "stuff" that's claimed comes down to deciding whether a marginal plausible effect is worth an additional demonstrable expense. Sometimes it is.

For ordinary automobile use, the convenience is in the opposite direction, and the cost is not capable of justification unless one wishes to just take it on faith that some vague "betterness might exist." (i.e. it makes you feel good to "buy into" something)

John


14 Nov 06 - 12:39 AM (#1885273)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

Spaw -

Agreed: you can get any product in "decent" or "junk" versions and lots of go-fast stripes are a dead giveaway of shitty performance (usually).

I have one good dial gauge that I refer to for my "calibration standard." I don't know that it's incredibly accurate but it's good enough. I have one digital that I use quite a lot because it's convenient, but I cross-check occasionally with the dial. It's not a "bottom of the barrel" digital, although not particularly expensive.

I have about five good pencil gauges, simply because I need vastly different ranges for tractor (10 psi), auto (30 psi), sport bikes (55 psi) and touring bike (75-90 psi), and because one tire is more accessible with a "two headed" gauge that I can "hook" the stem with.

Then of course there's the can of "retired gauges" that are too good to throw away but bothersome to use, mostly because of old hard seal gaskets that cause some leakage if you're not extremely careful about how you hit the teat.

John


14 Nov 06 - 12:43 AM (#1885276)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: Peace

"itogen has a larger molecule than some of the elements in air"


14 Nov 06 - 12:50 AM (#1885278)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: The Fooles Troupe

"Nitrogen has a larger molecule size than the molecules of some of the other elements in air"


14 Nov 06 - 01:42 AM (#1885287)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

But is itogen like the well known unobtainium or is it more like ultimatium, the two engineering materials on which designers most often base their projects?

John


14 Nov 06 - 03:55 AM (#1885323)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: Paul Burke

Not defending nitrogen in tyres, it's bull, but you can't calculate the molecule size from the atomic weight. Both nitrogen and oxygen molecules comsist of TWO atoms, and the molecule size will be almost entirely dictated by the length of the bond between them.

On that basis, nitrogen (and oxygen) will have larger molecules than any of the monatomic inert gases, but (probably) smaller than carbon dioxide.


14 Nov 06 - 08:19 AM (#1885412)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: The Fooles Troupe

Properties of the Total Charge Distributions*
A2 Re Length Width Nonbonded Radius
    Molecule Atom
Li2 5.051 8.7 7.8 1.8 3.3
B2 3.005 9.8 7.2 3.4 3.4
C2 2.3481 8.5 7.0 3.1 3.2
N2 2.068 8.2 6.4 3.1 3.0
O2 2.282 7.9 6.0 2.8 2.9
F2 2.68 7.9 5.4 2.6 2.8

*All distances are given in units of ao = 0.52917 Å.

damn - well look here then...

http://www.chemistry.mcmaster.ca/esam/Chapter_7/section_2.html


14 Nov 06 - 08:22 AM (#1885414)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: The Fooles Troupe

Helium and Nitrogen Sizes
http://www.newton.dep.anl.gov/askasci/chem00/chem00243.htm


14 Nov 06 - 06:27 PM (#1885857)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

The thermal conductivities of Pure Nitrogen and Pure Oxygen are not too much different, but it is true as a general rule that the thermal conductivity of a single pure gas is somewhat higher than when another gas is mixed in. A mixture of two gases, such as nitrogen and oxygen, would be expected to have a "cooling ability" less than the better of the two, and in many cases less than either of the two alone.

Note that the definition of "general rule" is "anything that works except when you rely on it."

The use of pure, or nearly pure, nitrogen for racing, based on improved tire heat dissipation thus has some credibility; and it's quite likely that a search would turn up some fairly persuasive accurate tests that will confirm this. I might look for such information if I were into racing, and the "prevailing opinion" probably would be sufficient that I'd use it anyway for racing.

Heat rise in tires even in normal passenger vehicle use can be "noticeable," but except in very rare cases is not sufficient to affect performance, safety, tire life, or fuel economy.

The exception to the significance of heat rise in normal uses is that a significantly underinflated tire can generate enough heating to be dangerous. Using pure nitrogen won't affect the fact that poor maintenance can kill you.

I do know personally a few people who make a habit of drivin' 'cross Texass, 2 or 3 hunnert miles at a trip, when the air temp is 105F, the pavement is at 180F, at speeds of 70 mph (the legal limit) or higher, on the "gimme the cheapest ya' got" tires from Wally World. I've never known one to blow a tire due to heat - except where the tire was "flat" when they left. They replace when the tread looks like a hobo's shoe soles, and the sidewalls resemble the baby that the dingoes got to.

I don't ride with them much (except possibly for local trips and with my teeth (etc.) clamped pretty tight); but their experience under "abusive conditions of ordinary use" sort of says that the heat thing isn't much of a problem in "common use."

(Feel free to discount this "argument" as "anecdotal" and "not worth a shit," 'cause that's what it is.)

Proper maintenance, including inflation, and selection of tires appropriate for your driving habits are your keys to safe and happy motoring. For most people, inflating with nitrogen is just speckled paint and go-fast stripes. If it makes you feel better, that's fine, because it won't hurt you except in your pocket; but it's not on my list.

John


14 Nov 06 - 06:39 PM (#1885877)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: catspaw49

For all concerned........

The main reason that nitrogen is used in racing is predictability. Tire pressures are critical to handling especially on racing tires which are much different than passenger car tires. In circle track racing, pressures are changed by half pound increments from side to side to change the stagger. To get more forwad bite and roll through the center of a corner better,a crew chief might add a pound to the right rear, a half pound to the right front, and go down a turn on the track bar. The only way a multiple change like that happens is if you know how quickly and by how much the pressure will increase as the tire heats up.

Nitrogen will not do diddly squat for your passenger car....period.

Spaw


14 Nov 06 - 06:42 PM (#1885883)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

If Spaw and I keep agreein' I'm gonna haf ta take up public fartin' just to show my respect.

John


14 Nov 06 - 06:52 PM (#1885891)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: catspaw49

Shoot John, I pretty much always agree with you but by the time you're done there isn't much left to be said! The best I do is add some mini comment where I might have specific knowledge.

LOL...I thought about getting into the speed ratings and aspect ratios of tires in relationship to wear and handling, but then thought better of it.

Spaw


14 Nov 06 - 06:55 PM (#1885893)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

Speed ratings are one of the things lots of people don't seem to know exist. Might be worth an essay. I'm more concerned with load ratings mostly, since my load's so big.

John


14 Nov 06 - 07:21 PM (#1885921)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: catspaw49

You realize of course that's a "loaded" statement......and I'm just going to leave it loaded.

Spaw


14 Nov 06 - 09:13 PM (#1886017)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: JohnInKansas

gee golly Spaw.

I'd almost forget how the simple exchange of pleasantries between a couple of fellas with true class, culture, and good taste could be such a relief from the humdrum of trying to solve people's petty problems.

Perhaps we should try this more often.

John


15 Nov 06 - 04:03 PM (#1886113)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: catspaw49

Probably so John, but where do you think we can find a couple of fellas with with true class, culture, and good taste?

Spaw


16 Nov 06 - 02:21 AM (#1886165)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: The Fooles Troupe

Ahem...


16 Nov 06 - 11:35 AM (#1886357)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: frogprince

This whole thread has been a gas...


16 Nov 06 - 07:27 PM (#1886518)
Subject: RE: BS: Nitrogen in your Car Tires? Bull Or Not
From: The Fooles Troupe

But not really Mudcat Classical Gas...