Nitrogen in tires

[partsman]

Just wanted to let everyone know that we offer Nitrogen machines and related supplies, as well as a host of other service support product to the shops at factory direct prices. Brake lubricants and noise treatments, A/C treatments, EVAP machines, carbide lathe bits, drain plugs, flexhones, road hazard polices and much more is available. Our family has been in the automotive supply and service field for over 40 years and have always worked direct with the shop owners, since we too have owned shops and experienced how difficult it is to make them profitable. We additionally offer free tech support on a variety of services, to help bring techs the most up to date technologies and procedures. Thanks, we look forward to being of service to your and your techs. Sincerely, Gary www. GWRauto .com

[autoguy]

Just wanted to let everyone know that we offer Nitrogen machines and related supplies, as well as a host of other service support product to the shops at factory direct prices. Brake lubricants and noise treatments, A/C treatments, EVAP machines, carbide lathe bits, drain plugs, flexhones, road hazard polices and much more is available. Our family has been in the automotive supply and service field for over 40 years and have always worked direct with the shop owners, since we too have owned shops and experienced how difficult it is to make them profitable. We additionally offer free tech support on a variety of services, to help bring techs the most up to date technologies and procedures. Thanks, we look forward to being of service to your and your techs. Sincerely, Gary www. GWRauto .com

 

Is there a huge calling for Nitrogen in tires?

[partsman]

Just wanted to let everyone know that we offer Nitrogen machines and related supplies, as well as a host of other service support product to the shops at factory direct prices. Brake lubricants and noise treatments, A/C treatments, EVAP machines, carbide lathe bits, drain plugs, flexhones, road hazard polices and much more is available. Our family has been in the automotive supply and service field for over 40 years and have always worked direct with the shop owners, since we too have owned shops and experienced how difficult it is to make them profitable. We additionally offer free tech support on a variety of services, to help bring techs the most up to date technologies and procedures. Thanks, we look forward to being of service to your and your techs. Sincerely, Gary www. GWRauto .com

 

 

Installing nitrogen in tires was probably the fastest growing service in 2008, for automotive service centers. In just the last 3 years over 25,000 nitrogen system have been sold, that's more than any other piece of equipment in the at price range. Within 5 years all new vehicles will come factory equipped with nitrogen when delivered, how will you be able to service them if you don't have a filling system? I have heard a few shop owner say they will just fill the tires with air when they need to balance, rotate or align a vehicle that comes in with Nitrogen. My response to them is... How do you think the customer will react when they find out you ruined the service they paid $50 for, a few weeks or months earlier?

 

Bottom line, there is not one negative for Nitrogen inflation! Every value, TPMS, corrosion, excessive heat, expansion vs contraction, blowouts, accidents, wasted fuel, excess emissions, loss of life, etc, is virtually immeasurable. Everyone needs to be offering nitrogen, even pushing nitrogen, as it is a valuable safety item for the vehicle owner. Additionally, since cost is pennies to the shop, it has become a great new profit center for owners.

 

You can find a lot of the statistics and details on the safety items at our web site... www. Premier Nitrogen .com

Thanks for the comment to my post, I would be happy to speak with anyone that has questions on this subject.

[xrac]

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[Joe Marconi]

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[autoguy]

Nitrogen is not a common service in my area. Altough many tire dealers are using it has an upsell. I understand the benifits, just not comfortable with yet. Maybe I'm old fashion.

 

I do not..but I know of some shops in higher income areas that are doing it and a couple of tire shops. Once I see the local Firestone's Goodyears, and Sears Auto centers doing it..I will look at it more.

[Joe Marconi]

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[partsman]

The jury is still out for me. But I will look into it.

 

Just a thought about Nitrogen and a response to a few comments I saw above. I have been working on cars for 30 plus years so technology has changed faster than the weather, unfortunately some shops don't seem to be quite as fast when it comes to keeping up. Since the introduction of TPMS there has been an explosion of new related service. You can't just tell your flunky to go rotate that customers tire and forget about it. Likewise we are seeing cars come in with complaints that there is "a light" on sometimes, or question like "what does that light on the dash mean?" Amazingly, we sometimes get calls from techs that didn't realize there was a difference between a flashing MIL and a steady one.

 

One think for sure is Nitrogen will be in every vehicle within the next 3 to 5 years. You can sell Nitrogen service now and pay for you equipment in just a few months or, once it is everywhere you can pay for the machine yourself. Don't think you won't have to have one either. When a car comes in to the shop and it needs an alignment, rotation, balance, front end work, etc... what is the first thing you usually do? Fill the tires to the proper inflation number, per door sticker suggestion. How will you do that when the vehicle has N2 and you don't have a machine? I don't think you are going to want to say, " I did your new ball joints but you now need to take it to the shop down the street to do the alignment". Worse, you don't just put air in and ruin the customers $40 investment. Can you imagine what he would say if he found out or saw your tech doing this? This is no joke, it will be reality soon.

 

I mentioned TPMS lights going on an off and what a hassle it is to explain to a customer that it is sometimes just the weather causing the problem. We just did a training class at one of the largest UTI schools a few days ago, the whole 8 hour class was on TPMS and problems that are coming. Did you know that you have to torque the Schrader valve stem core to an exact micro inch measurement, and that ther are two different nut torque setting on the same model some times? How many techs do and or know that? The number one service problem / complaint in the dealership this past year was TPMS related. Since the dealers are all going to N2 to solve this, over 30% have N2 equipment, you are going to start seeing more and more vehicles come in with N2.

 

Setting up N2 is not expensive for a shop. Fact is it will pay for itself faster than ANY other piece of shop equipment, usually between 3 and 4 months. Additionally, what service do you do now that has a 95% profit margin, takes 10 minutes and has virtually zero labor? I can't think of one, please let me know if you can. The biggest benefit though, is saving lives. Over 660 people died in 2007 just from under inflated tires, N2 and TPMS is bringing that number down base on the newest numbers.

 

Just may ranting again. Please don't think I am just trying to promote a product, I am a tech at heart and love to work on cars. I spend more time in our shop/lab working on vehicles than I do in the office trying to sell things. I'd like you to know that I believe in what I manufacture and that our customers are our most important asset. Please feel free to call me any time if you would like to talk about N2 or any subject, I am always ready to talk shop. Gary 1(800) 266-4497

[xrac]

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[Joe Marconi]

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[partsman]

These are all excellent points. The auto service business is getting more and more complicated and it seems that more time will needed on the services that were once considered gravy jobs. But, where are we headed with all this. Technology is great, but someone needs to pay for it. We cannot expect a shop to invest in all the training, tools and equipment and not adjust its price structure accordingly.

 

Will the national accounts get onboard with the rest of the independent shops and charge accordingly? The only way to solve these issues is with proper training, proper tools and proper equipment. There is no other way.

 

I have seen the transition from points to electronic ignition to computer controlled ignition systems. I have no doubt that we will conquer whatever comes our way. As far as nitrogen is concerned, all the issues pointed out will be a big problem until it becomes standard.

 

 

Hi guys,

 

I agree and disagree with the two comments above, I'll try and explain. Yes we need to get paid for what we do and for the added education, administration, etc, etc, that is now needed to service vehicles. Unfortunately I doubt if independents will ever be on a level playing field with dealers or national accounts, so what they have to be is smarter. The old adage of "work with your mind and not your hand" certainly applies here.

 

As to N2 profitability, please take a look at the sales number chart on my Premier website. It shows how, filling only 10% to 20% of your daily car count, can easily produce $500 to $1000 in net profit per month. I can't see how any shop, no matter how big or small the town, could not talk 10% of their customers into Nitrogen service. In most cases, the shop easily sells 50% and more of their base with little effort. Almost everyone has now heard of Nitrogen, we just need to clarify the facts a little and they will be ready to move forward.

 

Actually, regarding xrac's comment, having less N2 competitors in the neighborhood is a good thing. If you do the first service, or even if you don't, those who have nitrogen their tires will need to return to the shop that has a machine to have them topped off. When they come back in, it's an opportunity to inspect and find additional services that might be needed. What a great opportunity! As to being highly profitable, what service takes 3 minutes of actual labor, yet produces $20 to $30 in net profit? Especially one that you can do over and over again, day after day.

 

As to being a big problem until it becomes standard, again I disagree. Base on the feedback we see from cap sales, the nitrogen business is growing at a rate of about 100% to maybe 150% per year nationwide. If a shop waits they will be the looser because the cost of a system is, at this time, is being covered by sales. When all the dealers and national chains have it and the price for the service is free, who will pay for your machine? Remember you will have to buy one to be "in business", when everyone has one. If someone told you 10 years ago that you would be spending $20,000 on a scan system, or $5,000 on an A/C or Trans machine, or $10,000 on a tool box, we would have told them they were crazy. But today we do it, with little though.

 

On this one, think ahead and make it happen when profit margins are their highest. Don't wait for the guys that are sleeping to wake up, it will be more of a burden on your wallet then. One thing I forget was the use of the Motor Club to make sales easier. By throwing in the Road Hazard Protection package, a value of about $100, nitrogen service becomes a better value to your customer. At say $39.95, they are really getting about $150 worth of net benefits. Additionally, if anything happens to the car for the next year, it will be towed back to the shop for free. (See www.PremierMotorClub.com for details)

 

Thanks for your thoughts, I hope this makes sense and that you have the opportunity to investigate N2 service further. Gary ( The chart is at... www.PremierNitrogen.com )

 

P.S. We actually have many tools and products that I developed or discovered, that quicken labor time, reduce comebacks and or add additional revenue to existing services. If you implement them into the shop, it's like getting paid more for what you do. Feel free to check some of them out when you have the time, they work and used by thousands of shops daily. Hope this info is of value, the items are at... www.GWRauto.com

[Brianp]

I add nitrogen if it has the green caps. I use my evap leak tester to do it. But I would never sell the service sinceI am firmly aagainst its false advertisment and lack of REAL world benifits.

[GobblesAuto]

Isn't air 78% nitrogen?

 

GM's Position on the Use of Nitrogen Gas in Tires

 

General Motors does not oppose the use of purified nitrogen as an inflation gas for tires. We expect the theoretical benefits to be reduced in practical use due to the lack of an existing infrastructure to continuously facilitate inflating tires with nearly pure nitrogen. Even occasional inflation with compressed atmospheric air will negate many of the theoretical benefits. Given those theoretical benefits, practical limitations, and the robust design of GM original equipment TPC tires, the realized benefits to our customer of inflating their tires with purified nitrogen are expected to be minimal.

 

http://www.gm.com/corporate/responsibility/safety/tire_safety/manual.jsp

[gravysuckinpig]

Isn't air 78% nitrogen?

 

GM's Position on the Use of Nitrogen Gas in Tires

 

General Motors does not oppose the use of purified nitrogen as an inflation gas for tires. We expect the theoretical benefits to be reduced in practical use due to the lack of an existing infrastructure to continuously facilitate inflating tires with nearly pure nitrogen. Even occasional inflation with compressed atmospheric air will negate many of the theoretical benefits. Given those theoretical benefits, practical limitations, and the robust design of GM original equipment TPC tires, the realized benefits to our customer of inflating their tires with purified nitrogen are expected to be minimal.

 

http://www.gm.com/co...fety/manual.jsp

 

 

i have heard of nitrogen inflation - but never really paid much attention to it to even know what the "theoretical " benefits are. seems like another gimmick to me. .... ok i just googled it... correct me if im wrong... but they are saying the nitrogen molecules are larger than the oxygen molecules therefor dont leak as fast?..thats all well and good but a hole is a hole and a leaky rim is a leaky rim and molecule size doesnt apply there... what does apply is the cost of the customer to refill their tires .... call me old fashioned but air is free and has been doing a wonderful job since tires were invented... and i still refuse to buy bottled water also.... all these new things people are comming up with for cars.... you would think by now someone would come up with a fuel thats cheaper than gasoline that can be manufactured in large quantities easily....i have a news paper aticle thogh - of a guy that lived in my city(columbus, ohio) who modified an engine to run on plain water - and no crap he had a lunch meeting with some arabs and hours later he died.... said it was heart failure - his engine disappeared but rumor has it one of his relatives took it and has it hidden somewhere. you can google it.no sh$t.

[partsman]

Guys,

 

I really can't believe your comments as its been a year since I posted rebuttal answers to the most disputed arguments regarding Nitrogen. We are far beyond what I said now, as over 40% of the dealerships and nearly 20% of the private shops in America now have nitrogen. I would love to address the issues of the above three posts, but most of them have already be covered. I will say, concerning the info from GM, aren't they the company that said you did not need to flush brake fluid about 10 years ago but now highly recommend it?

 

Regarding the rims and other parts leaking, read my web site and the tech discussion on rubber and you will learn that 70% of the air that leaks out of a tire "goes through the rubber side wall". The smaller molecule with pass through and the nitrogen will not, base on the comparison of the rubber striation configuration of tire molecules. When these powerful molecules of corrosive oxygen line up one by one and begin their march through that 1/2" or so of rubber... they actually eat it alive, slowly, day by day. We on the other hand, keep feeding it by putting in more oxygen when it get 10 pounds low. Ouch! that is not to smart on several fronts. Did you know that a tire, just 8-10 pounds low, will operate at double the temperature it does when correctly inflated?

 

Gentlemen, this is science... not mystical smoke and mirrors or a conspiracy to make money! You are going to need to study and let loose of the old wives tales that some seem to still believe in.

 

If you read this and still have doubts about N2 in tires, I must feel sorry for the consumers that are going to miss out on the benefits of this valuable service.

 

J.M. Baldwin of FORD MOTOR Co, (Baldwin, JM, Bauer, DR, Ellwood, KE, Passenger Tires Inflated With Nitrogen Age Slower, Rubber and Plastics News, September 20, 2004) clearly established that passenger tires inflated with nitrogen age slower. In his work, "tires inflated with 96 percent and 99.9 percent nitrogen were oven aged at 60C (140F) for three to twelve weeks. For comparison, tires inflated with either air (80%/20% or 50%/50%) nitrogen/oxygen were oven aged alongside the nitrogen inflated tires". "The tires inflated with more than 95 percent nitrogen do not appear to change very much from the new tires even after 12 weeks in the oven, whereas the tires inflated with the oxygenated media change dramatically, even after three weeks in the oven." Further analysis validated Baldwin's conclusions that, "...tires inflated with more than 95 percent nitrogen do not appear to change very much from new tires." After twelve weeks of this very aggressive laboratory aging condition, Baldwin concluded that, at 12 weeks tires inflated with 96 percent nitrogen......the beginning of oxidative degradation can be seen. Nitrogen inflated tires, however degrade far slower than tires inflated with the oxygenated media.

 

It is based upon this 96 percent nitrogen finding that... "it is not recommended to exceed 4 or 5 percent oxygen in the tire".

 

Other Baldwin conclusions were "the oxidation of the steel belt rubber is truly driven from the contained air pressure .... the skim may be oxidized slightly from the outside when nitrogen filled, but the rate of degradation is significantly lower than when the tire is filled with air" Baldwin demonstrated that the peel strength changes in the 95 percent nitrogen exposed samples progressed at a much slower rate than the samples exposed to air. The fact that he was still able to see very slow oxidation in the 95 percent nitrogen exposed samples amplifies the expectation of a loss of the nitrogen durability benefits as one goes to lower levels of purity.

Baldwin states: "The overall conclusion of the study is: When nitrogen is used as the inflation media, the change in rubber properties is significantly slowed down or even halted."

To get the full impact of the research done on N2 tire inflation, please visit this link to see what Goodyear, Uniroyal, Volvo, Exxon, BF Goodrich, Michelin, Firestone, along with dozens of other major players in the tire industry really said on the subject. Likewise you can review what Mr. Harold J Herzlich wrote over several years of published technical papers, he is only known as the "Godfather" of rubber analysis. (Note: Be sure to take a look at his credentials at the bottom of the page)

 

http://www.nitrogent...en%20purity.htm

 

 

It's up to you now, I hope we can all finally move on with this matter.

 

Sincerely,

Gary

 

GWR Products

1(800) 266-4497

[Brianp]

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. 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 does it really matter to me since every single tire I’ve ever replaced was because of worn tread and not oxidation I see the moisture issue if you have a problem with wheels rusting out. I have never seen this happen. Ever. I have no proof that nitgrogen tires hold air better in fact you can scew numbers to point either way. It is a scam in my opinion and I wont sell it. Am I losing money maybe but I wont sell something I dont believe in.

[Brianp]

edit. Ive never had a nitrogen filled tire not be low at an oil change interval.

[xrac]

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[partsman]

Sorry, but I am perplexed. I can't figure out why some are fighting so hard on this proven science. The arguments you are using have all been disproved by thousand upon thousands of on the road tests by NHTSA, Private Fleets, Government Fleets and Military vehicles. Walmart is even going to N2 because they proved they could save millions of dollars on fuel and tires each and every year, while reducing pollution.

 

How can can anyone argue about saving money, reducing pollution, reducing our carbon footprint and most importantly... saving lives. Just because a tech does not understand a particular science, it does not mean that it does not work. They need to at least investigate the research and data that has been collected and reevualate their thinking on the subject, on a regular basis, as with any part of the car.

 

Graham's Law was mentioned as some kind of proof that N2 vs O2 is not that relative to the tire industry. Well the scientific community disagrees, based on miss application of the law. I have included one of explanations of this widely accepted erroneous applications, explained by a highly respected Dr. in the field. (Note: This is a serious discussion and needs to be read throughly, although it puts to bed the arguments that N2 inflation is not a benefit to a tire.)

 

Are Nitrogen Molecules Really Larger Than Oxygen Molecules?

The correct answer, with respect to "permeation" is yes.

 

Graham' Law Explained: The Difference between Effusion and Permeation...

There's often confusion associated with the molecular size, molecular weight and permeation properties of oxygen and nitrogen molecules, and GNI is often called to task to explain why nitrogen actually migrates (permeates) out through the rubber of a tire slower than does oxygen. This is a difficult scientific principal to understand so here is a logical documented explanation of the reasoning, based on the expertise of Dr. Keith Murphy:

 

"Effusion" calculations are not appropriate for "permeation" of gas molecules through materials, such as the rubber of tire walls. There is a fundamental difference in transport occurring through "effusion" and transport occurring through "permeation".

 

""Effusion would be appropriate, if the O2 and N2 molecules were passing through a relatively large passage way through the tire wall, such as a leak. Graham's Law for "effusion" applies ONLY if the exit through which the molecules pass is relatively large compared to the size of the molecules and does NOT obstruct or constrain one molecule from passing through relative to the other molecule. O2 and N2 molecules are only slightly different in molecular size but both are very small. Thus, to constrain one molecule's (e.g., molecule of type A) passage relative to the other's (e.g., molecule of type passage, that passage way size must be fairly close in dimension to the sizes of the molecules themselves.

 

Graham's Law does not apply if the passage way is very small, as occurs for dimensions of passage ways in-between the polymer chains in a solid rubber. Where the dimensions between the polymer chains do indeed constrain passage of the larger size molecule, which is actually N2, compared to less constraint on the smaller size molecule, which is actually O2.

 

It is often mistakenly assumed that "molecular size" correlates directly with "molecular weight". O2 does have a greater molecular weight (32) than N2 (28), but O2 is actually smaller in size. Thus, O2 fits through the relatively tight passage ways between polymer chains in the rubber more easily than does N2. The difference is size between O2 and N2 is very small, only about 0.3 times 10 to the -10th meters (0.00000000003 meters).

 

Among the various descriptions of the sizes of molecules, that most applicable to transport phenomena is called the "kinetic diameter" of molecules. The kinetic diameter is a reflection of the smallest effective dimension of a given molecule. It is easy to visualize that a given molecule can have more than one dimension, which characterizes its size, if the molecule is not spherical. O2 and N2 are diatomic molecules (two atoms joined by a chemical bond or bonds), not spheres in shape but rather cylindrical in shape, akin to the shape of a tiny jelly bean. Thus, a "length" dimension of the cylindrical shape is a larger dimension than the smaller "waistline" diameter of the cylindrical shape. In transport phenomena, the molecule with the smallest effective waistline diameter is that which behaves as the smallest molecule, i.e., has the smallest kinetic diameter.

 

Literature reports of kinetic diameters for O2 and N2 molecules, derived from several different types of experimental measurements, give slightly different values, but all show that O2 has a slightly smaller diameter than N2. The following examples expressed in Angstrom units demonstrate this (one Angstrom unit is 10 to the -10th power meters, i.e., one-ten-billionth of a meter): from gas viscosity data, O2 2.96 and N2 3.16 (difference 0.20); from van der Waal's interaction data, O2 2.90 and N2 3.14 (difference 0.24); from molecular refraction data, O2 2.34 and N2 2.40 (difference 0.06). Other experiments, less applicable to transport situations, such as from closest packing, when the two molecules exist in a frozen solid state at very low temperatures, still show O2 to be a smaller size than N2 (O2 3.75 and N2 4.00, difference 0.25).

 

The reason that O2, despite a larger MW 32, has a smaller diameter than N2 MW 28, lies in the electronic structure of the molecules. As indicated by quantum mechanical theory of molecules, the electrons of a molecule form a diffuse "cloud" surrounding the nuclei of the atoms in the molecule. The electron cloud around the oxygen nuclei in the O2 molecule is smaller, more compact in size, due to attractive electrostatic interactions between the electrons in the cloud and the greater positive charge of the nuclei of the O atoms in the O2 molecule. Each oxygen atom has 8 protons in its nucleus, while each nitrogen atom has only 7 protons in its nucleus. Thus, the overall size of the electron cloud of the O2 molecule is smaller than for N2, in part because its electron cloud is drawn in closer to the O nuclei by he greater positive charge on the O nuclei.

 

The dimension of the molecule's electron cloud defines the size and shape for a given type of molecule. When one molecule bumps into another molecule, the outer-most extent of the electron clouds of each molecule repel each other in that local vicinity of the contact between the molecules. Each colliding molecule's electron cloud experiences a repulsion, due to the proximity to the like electrical charge of electrons around the other molecule in the collision. Since like electrical charges repel each other (like-repels-like), the electrostatic interaction between the electron clouds of the colliding molecules is repulsive. That repulsion effectively defines the size of the molecules.

 

O2 "permeates" approximately 3-4 times faster than does N2 through a typical rubber, as is used in tires, primarily because O2 has a slightly smaller effective molecular size than does N2.

 

A relationship that governs "permeation" is based on Fick's Law of Diffusion and Henry's Law of Solubilities, which takes into account the relative sizes of the molecules and their sizes compared to the very small passage way dimensions in the solid material (such as a rubber) through which the molecules "permeate". Combining Fick's and Henry's Laws yields the overall equation governing permeation of small molecules, such as gases, in material, such as rubbers and other plastics.

 

Let's call the rate of permeation of gas (i), Ji, J-sub-i, which is simply the volumetric flux of gas permeation per unit of time. Conveniently used units of Ji are cubic centimeters of gas per second, or cm^3/s.

 

Consider a sheet of the rubber, such as a section of the tire wall.

 

That flux of gas permeating through a material is directly proportional to the first three factors, below, and inversely to the fourth factor, below:

 

1. the area, call it A (in units of square centimeters, cm^2) of the sample of the rubber - More flux of gas would occur, if the area were larger, if everything else were the same; next,

 

2. the driving force for transport across the wall, which is the difference in concentration of gas (i) across the tire wall - for convenience with gases, a nearly exactly correct measure of this is the difference in partial pressures (pi) of that gas (i) on the two sides of the tire wall (i.e., pi inside minus pi outside) - Obviously, a higher partial pressure (pressure units are cmHg, centimeters of mercury, and remember that 76 cmHg = 1 atmosphere = 14.7 psi) inside versus outside means there is more driving force to promote transport across the tire wall; then next,

 

3. the intrinsic permeability P, call it Pij, or P-sub-i-sub-j, is the "permeability coefficient" for the particular material (j) for that type of gas (i) - Note that various materials, i.e., different types of rubbers or plastics will permeate O2 faster or slower depending on the details of solid state structures of the materials, and different types of gases will permeate each material faster or slower depending on the relative sizes of the gas molecules, as well as on how soluble the gas is in the solid material; then lastly,

 

4. the thickness L (in units of cm) of the material - you can see that if the tire wall were, say, twice as thick, one would expect half the permeation rate (flux, cm^3/s), all other things being equal.

 

Combine these four terms, and you get the permeation equation:

 

Ji = [ Pij x A x (pi inside - pi outside) ] / L

 

flux = permeability coefficient of gas (i) in material (j) of the tire wall multiplied by area multiplied by the partial pressure difference for gas (i) across the tire wall divided by the thickness of the tire wall.

 

Similarly, for the other gas (m), its flux would be:

 

Jm = [ Pmj x A x (pm inside - pm outside) ] / L

 

since it would have a different permeability coefficient in that same rubber (j) and a different driving force across the tire wall.

 

So, the fluxes for different gases will be different, depending on the relative magnitudes of the permeability coefficients of the two different types of gas molecules and the relative concentrations (partial pressures) of the two types of molecules on each side of the tire wall (i.e., inside vs outside).

 

From the early part of this discussion, you will now recognize that Pi, where gas (i) is O2, is greater than Pm, where gas (m) is N2, principally because O2 has a smaller kinetic diameter than N2 and thus O2 has a larger permeability coefficient than does N2 - actually O2 has a permeability coefficient in a typical tire rubber material, which is about 3-4 times that of N2 in the same material. Permeation of O2 and N2 is primarily determined by size effects, because at normal temperatures and pressures relevant to the discussions of tires, these gases behave almost perfectly as Ideal Gases. As such, the differences in solubilities of O2 and N2 in most rubbers and plastics are too small to contribute to differences in their permeability coefficients. The differences observed are essentially solely due to the slight differences in the size of O2 relative to N2.

 

In case you wish to do your own calculations, the units for P (the permeability coefficients) most often used in the technical literature are:

 

[ cm^3 x cm ] / [ s x cm^2 x cmHg ] and for convenience, a standard unit of permeability is called the Barrer, after Richard Barrer, one of the early pioneers in studies of permeation in materials, such as rubbers and plastics.

 

One Barrer unit is:

1 times 10 to the minus 10th power [cm^3 x cm]/[s x cm^2 x cmHg]

 

In Barrers, for a typical rubber material, the permeability coefficient P, is dependant on temperature, but at 25C (77F) for O2 is about 10 and for N2 is about 3.

 

I hope this helps clarify why O2 permeates faster through rubber than does N2 and a major aspect of why it is a good idea to significantly reduce the amount of O2 used to fill tires by replacing most of the O2 in air with enriched N2. Since N2 permeates through the tire rubber more slowly than would O2, using enriched nitrogen instead of air for tire filling contributes to better maintenance of the proper inflation pressure for the tire. Better pressure maintenance contributes to reduced tire wear, so that tires last longer and tire replacement costs are reduced.

 

A simple but approximately correct explanation of this lies in the mechanics of the flexing of tire walls. If proper inflation pressure is maintained, the tire wall most effectively bears the weight of the vehicle. If pressure is allowed to fall too low, extra flexing that occurs as the vehicle bounces somewhat along the road causes excessive mechanical fatigue of the structure of the tire. Similar to flexing a wire coat hanger, this fatigue can weaken the tire faster than would be the case were it kept inflated to a pressure more consistent with that intended in its design.

 

Dr. Keith Murphy

Air Products and Chemicals, Inc.

St. Louis, MO

 

 

 

If you are still following along, I would like to mention a few other items...

 

There was a comment about whether or not the tire would deflate fast with air vs N2. A few years ago Consumers Report did a very simple test to see what was true and what was false, regarding this issue. The test had nothing to do with cost vs value, it simply was done to find out the answer to the question... does air leak out faster than N2. Here are the details...

 

Our recent blog post, "Tires - Nitrogen Air Loss Study", looked at using nitrogen in tires. So far, it has generated a lot of interest. In fact, that post has received more comments than almost any other. Among the comments were many questions--more than could be addressed in a simple comments format.

 

Senior tire engineer and program leader Gene Petersen,

 

(Gene Petersen is a genuine tire guy (aka nut) with about 30 years of experience in the tire field, first working for Armstrong Rubber Company and then for Pirelli as a test engineer. He has worked on passenger, light-truck, medium-truck, and even agricultural tires, assessing their performance and trying to measure their strengths and weaknesses. For more than a decade at Consumer Reports, Gene has applied his expertise to testing and reporting on the performance of tires for passenger cars and light trucks. As Gene says, tires define the personality of the vehicle--without a good or proper tire, people often shortchange their safety and their car's capability. When not testing tires, Gene helps out with the CR auto engineers, evaluating new cars and trucks. This gives him a glimpse of the latest tire trends that will be affecting the replacement tire market.)

 

For quick background on the nitrogen test:

 

Consumer Reports wanted to find out if nitrogen is worth the price for passenger vehicles, so 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 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, the reduction was a 1.3 psi difference from air-filled tires. The average loss of air-filled tires was 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. Note that all tires lost air pressure regardless of the inflation medium, so consumers should check their tires' air pressure routinely. Additionally, no evaluation was done to assess the aging claim.

 

Note that this test is very simple but it does prove what we have been saying for years... N2 gas will maintain tire pressure longer than straight air. This is a test that definately addresses the migration of molecules through the tire wall issue. It proves that in a static condition, removes chance of loss through most any other outlet, there is a factor of permeability involved.

 

As to one other comment, I can't understand why someone would want other service centers in their area to have the same service. Would this not create competition and a lower price as time goes on? Likewise, if you are the only guy in town, wouldn't an N2 inflated vehicle have to come to you for a top off? Testing has been done and there is a correlation between the number of visits to a shop and the type of gas in a tire. The average number of yearly visits, for the first 5 years of a vehicle's life, doubles when the tires are inflated with Nitrogen. Are you still willing to pass up this free opportunity to have the vehicle back in your shop, your competition my not?

 

 

I don't know what more we can say on this subject as every argument had been debunked, by scientific testing, field testing and long term on the road testing. Nitrogen is not a gimmick, has absolutely no negatives, is safer, reduces pollution, saves lives, saves money, saves fuel, more comfortable to drive on, and much more. Additionally, I have not even touched on TPMS and how Nitrogen benefits them in numerous ways.

 

Thanks for reviewing the data and tech, I appreciate the time you spent. I likewise hope it has helped those open to continuing their education in our field, this service will be a major issue in 2011.

 

Sincerely,

Gary

 

GWR Products

1(800 266-4497

 

P.S. I am curious about how shops are going to service the millions of vehicles that will be stopping in, with N2 from the factory or a new car dealership. Please post your thoughts and plans on how you will balance, rotate and align those customers, I am curious. Thanks

[xrac]

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[gravysuckinpig]

would someone PLEASE order a nitrogen machine from this guy........ all kidding aside.... has anyone ever took off an air intake box and found one of those little metal tornado things? i have found lots and lots of them - or the little magnets on fuel lines...or maybe even an electronic rust inhibiting system (most likely on a rusting car)...

there have been sooooo many gadgets and gizmos sold to the motoring public all backed by "scientific" proof and tons of research that they really work....please excuse us all....the ones who actually deal with this stuff EVERY DAY if we seem skeptical. you are after all....a nitrogen salesman... can you blame us - after reading that last post with all the numbers and formulas... i came up with my own ,,

 

 

56%(5489)*2d= J+ ^533

 

 

if you add those together it means i call "bullshit" on the whole thing.

sorry joe kick me or ban me or whatever if you have to for that but but im not falling for it... no siiirreee

even if my customers would return to me over and over for their "nitrogen fix" i cant recommend a product i dont believe in.

 

especially if wal-mart is going to do it.

[partsman]

You are getting off the subject and issue with the comments you posted. Who's fault is it that a consumer does not know what TPMS is? It is the job of a shop owner or SR to educate the consumer on the importance of safety issues related to their car or truck. You might not be aware of this fact but deaths from tire blowouts have decreased about 30% since the mandatory installation of TPMS on US passengers vehicles in 2007. Would you want to be responsible for the death of someone because they say they don't want to spend the money needed to replace a dead sensor? Of course not, you would tell them TPM Sensors are a mandatory safety part and the part needs to be replaced if they want to maintain the integrity of the system and vehicle.

 

Regarding the repair of a tire that hit something and blew out, just fill a new one with air and get them back on the road. Why do you want to make a problem out of this when it is an opportunity? As I stated before, if there are limited machines in an area this situation is going to bring a customer to the shops that are smart enough to have nitrogen service. How can that be bad for the shop? How can that be bad for the customer? You get to look at the car for other services and the customer get at check up safety components and more.

 

If you received Nitrogen with a new a new or used vehicle, I guarantee you will want it again when you buy new tires. Numbers don't lie, over 75% of first time users ask for N2 when they buy new tires. Why? Because they ride better, they require less maintenance, they get better mileage, they are safer, they last longer and their TPMS does not go crazy when temps spike or dip. If you are worried you can't sell N2, bundle it with other services that are of equal or greater value. (I.E. We have an Emergency Roadside Assistance program at half the retail price of AAA. You simply offer your customer a bundle that included an oil change, or a brake service, or a ???, etc, etc, plus give them the N2 service for FREE. Who would turn that down? You make more on all the services because the Motor Club has a perceived value of over $100, but cost you less than $10.)

 

I feel it is a tragedy consumers are not educated on new technology, especially when it involves lives. Would you allow a customer to disable the ABS system if it had a problem and they did not have the money to fix it? We all need to be aware that it is our job, it is our responsibility, to help our customers. I liken it to being a doctor... the owner of the vehicle brings his patient to you because you are the expert with the proper training to bring the vehicle back to proper health.

 

Sorry for being blunt, but this is a more than selling parts and changing oil.

 

Sincerely,

Gary

 

P.S. As a note, some of our best customers are in rural areas of this country. They bring in the new tech first, so they become the experts in that marketplace.

 

 

GWR Products

GWRauto.com

1(800) 266-4497

[partsman]

would someone PLEASE order a nitrogen machine from this guy........ all kidding aside.... has anyone ever took off an air intake box and found one of those little metal tornado things? i have found lots and lots of them - or the little magnets on fuel lines...or maybe even an electronic rust inhibiting system (most likely on a rusting car)...

there have been sooooo many gadgets and gizmos sold to the motoring public all backed by "scientific" proof and tons of research that they really work....please excuse us all....the ones who actually deal with this stuff EVERY DAY if we seem skeptical. you are after all....a nitrogen salesman... can you blame us - after reading that last post with all the numbers and formulas... i came up with my own ,,

 

 

56%(5489)*2d= J+ ^533

 

 

if you add those together it means i call "bullshit" on the whole thing.

sorry joe kick me or ban me or whatever if you have to for that but but im not falling for it... no siiirreee

even if my customers would return to me over and over for their "nitrogen fix" i cant recommend a product i dont believe in.

 

especially if wal-mart is going to do it.

[partsman]

That was an incredible post, well here goes...

 

First, I am not actually a Nitrogen "Salesman". We are a manufacturer that helped create this industry with over 10 years of research in pneumatics, software engineering and finally the fabrication of a very sophisticated piece of equipment. Additionally, we hold patents, manufacture and distribute over 100 other items and products for automotive, aviation and the rail industry. Many of these unique items have won dozens of national and international awards for engineering, innovation and top products of the year. (I.E. Ceramlub, Pastelub, the Silencer, BrakeSoap, A/C Stop Leak Plus, Oil Filter Magnets, RadStrips, Premier Nitrogen Systems and many more). In other words, we have paid our dues.

 

I guess I'm shocked that someone would not believe proven, scientific DATA... actually the laws of physics ? I knew that some would not understand the calculations, but I put them in the post for those that might. I did not make it up by the way. These are the most respected men in their fields, not to mention test results from Consumer Reports, NHTSA, the US Government, Firestone, Goodyear, Michelin and many other industry leaders. I'm sure you are unaware of the sales numbers but the top end N2 unit we offer shops has surpassed over 5,000 units in just the last 3 years. As a jest rebuttal, I really don't need to "sell a unit"... to make my day. I actually did enjoy your ranting and the story regarding the Tornado was inspiring, are you aware that CR, Motor, Mark Salem and many others sent out reports that refuted all clams on that item. Obviously you see them because there are unscrupulous mechanic and or dumb ones that haven't got a clue.

 

As I have stated many time in past posts... I have be involved in automotive for over 35 years, do training at the OE levels and have a vehicle engineering background. What I bring to this forum is knowledge so please use it as you see fit, just don't short change your customer based on preexisting biases. My mantra is... When in doubt test it for yourself!

 

Sincerely,

Gary

 

P.S. Note that I had not posted on N2 for nearly a year. Obviously I was not pushing our product but was responding to some comments I felt needed addressing.

 

 

 

[DewayneP]

Here's something to chew on: Per Consumer Reports:

 

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.

 

 

 

In other words, check your tire pressure! Don't fall back on a false sense of security because you had your tires filled with nitrogen. I see lawsuites in the near future claiming that the driver didn't feel as though he had to check his tire pressure because nitrogen doesn't leak out from the tire.

[xrac]

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[Joe Marconi]

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[Brianp]

I add nitrogen to tires that already have it. But its still a subject that is toal garbage in my opinion. Anyone can scew #'s to favor there argument. But in real life situations nitrogen does not help a tire period. Does it keep a tire cooler at 150 mph? Possibly but that isnt a real life situation. Does it keep the inside of a tire from rotting as fast? Maybe but the outside or tread will still rot so a bogus claim. Will it keep moisture out of the wheel? Possibly but again I have never seen this as an issue EVER. Does nitrogen keep tires from losing air? NOPE I have to add nitrogen to every car that has it in them everytime the oil is changed and there tpm light some on just like the rest. 50% of the tire warning light calls I recieve have nitrogen in them. These are things I see in my shop. Nitrogen is a gimmick in my opinion. I have never seen any real life instances that would allow me to ethicly sell it to my customers. Consumer reports has said alot of things over the years that have been proven false. Like most tests and articles sometimes it comes down to the info given to the author or the $.

[gravysuckinpig]

wow....someone picked a good topic to talk about it seems...

[Southeast Tire Co.]

You certainly have plenty of scientific data to back up the claim that nitrogen is superior to air. You also cite the fact that nitrogen use will be more widespread in the future. What you do not mention is the public's perception and acceptance of it. You are getting feedback from very successful shop owners who are telling you that they view it is an up-sell item and not a necessity, that customers are not requesting it and, in some cases, are moving away from it.

 

My primary business is tire sales and service. My business is in a large city (600k+). I can think of 2 instances where a customer called or walked in looking for nitrogen in the past year and I service a heck of a lot of vehicles. When I see the green caps, I explain to them that I do not offer nitrogen inflation. It is not something people want or care about and I have never lost a customer because of it. With TPMS technology, proper inflation had become less of an issue. It has made people more aware of their tire pressure and consequently reduces problems that we used to see more of (uneven tire wear, blow-outs, poor gas mileage).

 

I group this gimmick into what I call the "Jiffy Lube" method of up-selling. You go in for an oil change and, before you know it, you need an air filter, wiper blades, a coolant flush, and diff oil change. Sell them everything you can by telling them they have to have it and will suffer the consequences if they don't. I despise that type of sales mentality and so do most customers. I will not sell something that only offers an arguably minimal benefit at a premium price.

 

It is snake-oil sales at its finest and I won't bite on it and neither will the consumer in the long run.

 

*edit - spelling

Edited January 27, 2011 by Southeast Tire Co.

[Gary A]

Here's another article on nitrogen

 

http://www.industryleadersmagazine.com/ford-motor-company-supports-nitrogen-tire-inflation/

[TheTrustedMechanic]

In my opinion it is very simple, the OP is a marketer for nitrogen generation machines and will fight to the death to defend the position that every car must have nitrogen in the tires in order to generate more demand for his product. The claim is that, "The arguments you are using have all been disproved by thousand upon thousands of on the road tests by NHTSA, Private Fleets, Government Fleets and Military vehicles." Well it would be interesting to know all of the facts that were available and also what facts were used to try and prove this position. As we've seen in politics lately, figures don't lie, but liars figure. Any position can be substantiated if you select from the facts and statistics available the ones that support your position.

 

As for the thousands upon thousands of road tests, what was the intent of those road tests? If they were to prove the effectiveness of of nitrogen as opposed to compare the performances of each inflation gas composition then the results would be skewed also.

 

As for the assertion that, "over 40% of the dealerships ... now have nitrogen," if it was so important, wouldn't 100% of dealerships have nitrogen because of the manufacturer's would require it. And in my area almost all of the dealerships aggressively sell "maintenance fluid flushes" whether they are needed or not, so claiming that because the dealers do it makes it right is a patently false assertion.

 

And just like BrianP wrote, I agree, "The real questions are: a) how do you keep oxygen on the outside of your tires from causing oxidation?, and does it really matter since every single tire I’ve ever replaced was because of worn tread and not oxidation?" I have had a couple customers need to replace their tires due to oxidation and degradation of the sidewall, but that was on the OUTSIDE of the tire, not the inside. So the question still begs what difference does it make if you eliminate all oxidation on the inside of of the tire and extend it's life span beyond what the atmospheric and wear conditions on the outside of the tire will permit?

 

When credible evidence can be provided, from independent peer reviewed sources, not self-interested nitrogen generation equipment manufacturer/sales sources, then maybe I will subscribe to the practice. And even then it will be more cost effective to buy a tank of nitrogen from the local industrial gas supplier than to buy the grossly overpriced nitrogen generator and the consumable permeable gas membranes.

 

Regardless though, this whole thread has been an attempt to market a product to the members of this forum, and I for one take offense to that. i did not join Auto Shop Owner to open myself up to sales efforts. Advertising on the pages just like all other webpages you visit is one thing, a direct sales pitch posed as a forum post is insulting and abusive of the members.

[GeeZ]

Personally, I believe it is a lot about nothing.

[xrac]

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