p_mentir

Saw an advert at mercedes dealership:

They will fill your tires with nitrogen (al la Nissan GTR) for $150-$200 (I forget exactly how much, but definetly over $100). Is it worth it or just a waste of money?

Loosely quoting Top Gear, Nissan fills the GTR tires with nitrogen due to its stability at various temps - pressure remains much more constant over various driving conditions etc.

I'm wondering if it's worth the money and if it lessens the strain on the suspension.

Anyone have thoughts on this?

tusabes

costco does this for free. Many tire shops do it for $5-10 per tire. Paying $150-200 is taking advantage of wealthy uneducated customers.

Heres a Consumer Reports analysis
http://blogs.consumerreports.org/car...nitrogen-.html

My opinion is Its an utter complete waste of money on a street car AS LONG AS YOU CHECK YOUR PRESSURE REGULARLY, since the main benefit is slower air loss.

For people who never check their tires, they will lose less over time using nitrogen. But you can make sure your tires are correctly inflated simply by checking them.

besides slower pressure loss, unless you are racing at the speed limits of the tire rating, where tire pressures and condition means the difference between life and death, its a waste.

Regular air is comprised of 78% nitrogen. A nitrogen tire fill is about 95%, if cycled several times to remove as much "normal air" as possible. So its not like its 0% vs 95%... Its a really meaningless difference on the street.

So its just as useless in a street driven GTR, not on the track.

Some people claim a nitro fill reduces "oxygen rot" of the rubber. Even if you have nitro fill on the inside, the outside is exposed to air. And its the outside of a tire that suffers most rubber rot from the sun and oxygen...rot rarely happens from the inside out.

Bottom line: the dealer is ripping you off. If you are determined to get a nitro fill, dont pay more than $5-10 per tire. I did some googling and found many dealers sell a "go green auto club" package who will charge about $40 to do a nitro fill plus give you a free roadside assistance plan.

MRAMG1

I have posted this many times on all of the forums.


SAVE YOUR MONEY AS IT A WASTE

They will still loose pressure over time, albeit at a SLIGHTLY slower rate.

They will still expand and contract with temperature

PV=NRT

If it is free, why not, if costs money, SAVE it.

p_mentir

Thanks much!!

I'm new to the forum and I apologize if I missed prior posts/threads on this. I do drive over 100mph often enough, so i guess i'd pay 20-40 bucks for it, 150-200 seemed a little extravagant.

MRAMG1

Speed has NO effect on what gas you put in my friend

PV=NRT works for ALL gases and mixtures as in the case of air.

The MAJOR reason why some racing bodies use it, is that AIR has water in it. And while racing it is easy to get a rim over 212 F, and that can cause the water, in the air, to flash over to steam which RAPIDLY expands.

SAVE your money as you will NEVER see these temps on a street car with stock brakes.


Edit: Another little web site quote on the beloved Nitorgen BS

Nitrogen proponents say that the nature of the gas means it's less prone to leaking out over time through the pores present in rubber tires. But most air leakage in tires can be traced to poor fit around the rim of the wheel or the valve stem, rather than gas permeating through the rubber.

Claims of nitrogen being more friendly to the rubber and wheels is also questionable, since most tires wear out the tread on the outside long before the inner rubber would go bad from exposure to oxygen. The same factors hold true for wheels, many of which are made from alloys, not straight steel. You're far more likely to damage a wheel from hitting a curb than see a wheel go bad from oxidation.

A good site that takes a contrarian point of view on nitrogen in passenger car tires is www.eng-tips.com, which is run by engineers.

When it comes down to a dollar decision, it's hard to argue that spending as much as $40 for nitrogen in a set of tires is a good fiscal move.

Even if you accept the arguments of proponents, at some point you are going to have to add air to your tires -- not even the most ardent nitrogen pushers will say that your tires will never lose pressure. When that happens, you're most likely to go to the corner gas station, put in a couple of quarters and pump your tire up with regular old air, which will mix with the nitrogen and degrade its benefits.

Save your money and just keep an eye on your tire pressures

p_mentir

LOL, i love it, i should send that to the dealership! Thanks again!

Velociabstract

If you track the car it could make a lot of difference depending on the tire. Tires have an optimum pressure and temperature. My current tires (Advan AD08's) increase 12 psi in the front and 8 psi in the rear from cold starting pressure. They reach between 170 and 180º after 5 minutes. The Advan AD08 sticks like glue until 38 psi hot, more or less. with less than 30 lbs starting pressure the tire rolls over, even with the stiff sidewalls. With plain old air I have to choose to be fast at the start and slow down after a few laps or start with real low pressure, go slow, and pick up speed later. Neither option is acceptable. I'm planning on filling with Nitrogen in the near future. If I can limit the pressure increase to 4 or 5 psi it will make the tire last longer and grip from start to finish. So, "is it worth it" depends on what tire you have and how you abuse it.

Les

p_mentir

I have not (and don't plan on) tracking my car. I drive fast on the highway, and I DO have increased tire pressure from when I start - at least according to the tire pressure monitor in my car. I try to keep the pressure around 34 psi (stock rims/tires) but it varies from 30 to 41. Typical range on the 2 hour commute (total) is 33-39.

I'm curious to see if you tires pressure is more stable after the nitrogen, but i'm starting to think it's not even worth a couple of 20's...

MRAMG1

That is why ALL tire experts recommend using a HOT tire pressure, NOT COLD. ALL racing tires are designed to work at a specific temperature range. And crews adjust the pressure to get them in their sweet spots, amoungest other variable.

Again, the pressure WILL still rise here people

You just aren't getting it.


PV=NRT

No matter what gas you use, if the temperature rises, thats T above, the Pressure, thats P above, HAS TO GO UP.

Side note: V is volume which is a constant here, well not perfect as the tire does expand slightly, N is the numbers of moles of gas which is a constant, and R is the Reynolds number which is ALWAYS a constant.

Two people on the C63 thread have already experienced this WASTE of money and have acknowledged this fallacy.

Guess what, even on Nitrogen, they sky rocketed their pressures when racing.

ALL GASES WILL EXPAND WHEN HEATED.

Believe the hype all you want, after all it is YOUR money.

Okay, I am done here.

EDIT: On a side note for the above driver, you are probably over driving your car, or your front rims are too narrow for the tire. Just a guess, as there could be MANY other variables here as well.

Velociabstract

To reach the target hot pressure you have to have a low start pressure. Right? To find the correct cold starting pressure the normal procedure is to run hard and heat the tire to full temperature, bleed off the excess until you reach your target hot pressure, let the tires cool all the way down to find the correct cold starting pressure. Where I race they don't allow tire heaters so I must start at 25 psi or in the middle of a race, come in and bleed off excess pressure. Clearly anything that helps reduce the pressure rise is beneficial for track purposes. On the street it's a waste of time unless your towing heavy loads. I've never seen severe pressure variations from only driving fast.
I don't pretend to be a great driver or know it all but I have a probe pyrometer and good pressure gauge and know how to use them. Yes my car is camber challenged and I can only get -2º in the front. I run stock size rims and stock tire size. As to why I want to try Nitrogen, I can fill up at Costco, refill and refill again. People I race against use it and recount that it reduces the pressure rise. Not temperature rise, pressure rise. BTW, I overdrove my car to the CCCPR 2010 Solocross championship in my class.

Les

MRAMG1

First thing my friend, I said over driving could be one of MANY issues. NOT the only. There are MANY reasons why you are getting your fronts THAT much hotter than the rears. AS a driver you should already know them. And I am sure you are aware that over driving is USUALLY the number cause.

Second Congrats on a solo championship

Nascar, F1, etc, sure as I explained above about water, and YES the occasional fire, as AIR helps combustion where as Nitrogen will not.

If you honestly think Nitrogen will help at a solo or open track day, have it.

Just DON'T be surprised to find out, I told you so. It will expand at almost identical rates.

Good luck my friend.

And YES, I am really not trying to bust your stones, trust me. You would know if I was trying to be a real *****

Velociabstract

Stock tire size is 225/40/18 in the front and 255/35/19 in the rear. If I could fit a 255 on the front I believe the pressure rise would be equal front to rear. The car is well balanced. I recently switched from Pilot Sport Cups to Advans. The AD08's consistently increase 4psi both front and rear more than the Cups. I don't have a know "dry air" source and imagine most people don't. Not to mention I live beside a tropical rain forest. That being the case, I'll give the nitrogen a try and let you know if, under my particular circumstances, I see a benefit. It's not always as black and white as you paint it to be. I don't think your a *****, just a touch arrogant. I appreciate the congrats. I don't doubt you, but I think it's worth a try. When these AD08's are in their sweet spot, they are as good as the Cups. I want to be able to start and finish near that spot.

Les

MRAMG1

A few questions for you.

1. What is your front rim width? I am hoping that it is 8" to properly support that tire.

2. The increase in temp, that you mentioned, sounds like the AD08's are a softer compound or have a softer sidewall. Either one would explain the increase on the the same car, and assuming same rims and driving style.

3. I never said it wouldn't hurt provided that it is free, I just said and know it really won't help either. It's the arrogant ***** in me, and a few decades of racing behind me

After all as someone else here said, I am an old fart

Good luck, and please respond back, good, bad or ortherwise

amdeutsch

Fart = methane NOT nitrogen AFAIK. Are you sure you got your gasses right?

Velociabstract

hahaha ..... old fart, a well seasoned one I hope. I'll let you know if it's a total waste of time and effort or not. (I realize you already know which one it will be) I'm an old peo as well, but relatively new to racing. Stock front rim width is 7 1/2. The AD08 has a real stiff side wall. As far as tire temperature, 170º is not hot, at least not that I'm aware of. I can't find information as to the optimum temperature for the Advan's but being a street tire I'm not surprised I can't find the information. They grip best (for me) at 36 to 38psi hot. The AD08's are 180 treadwear, the Cups are 80 treadwear with a soft sidewall.

What really has me worried is amdeutsch showing up in this thread. An infraction is sure to follow for advertising nitrogen with no Mbworld sponsership.

Les

amdeutsch

Velociabstract

How about an update on this. The constructive and educated observations of MRAMG1 convinced me to purchase proper wheels for track days. (Forgestar F14's) I now have 18x9 on the front with 245/35/18 tires and 18x10 on the rear with 275/35/18 tires. The tire temperatures increased, with plain old breathing air, 5 lbs in the rears and 6 lbs. in the fronts. So it seems I did indeed have too wide a tire on too narrow a rim for track usage. I haven't put nitrogen because it's just too far out of the way. If I ever do, I'll come back and post what I discover. So thanks for convincing me to do what I already knew but needed a push to follow through with.

http://www.youtube.com/watch?v=4ersL...eedwll&list=WL

Les

MRAMG1

Anytime my friend

Just glad to see it worked out for you.

Tropical

I purchased 4 new tires at Costco about 4 years ago. Costco fills those tires with nitrogen at no extra cost! Costco also will check your tire pressure and maintain it at specified pressure free! Why pay extra?

Welwynnick

Actually the Reynolds number relates to fluid dynamics, not thermodynamics.

R is the gas constant, 8.314 Joules per mole per Kelvin , which IIRC is the product of Boltzmann's contant and Avogadro's number.

But yes, its still a constant.

I think the idea of of Nitrogen filling is to help keep the inside of the tyre dry, so dry air should do fine. If there's any condensation inside, that will tend to cause greater pressure variation with temperature. Still, this wouldn't be at the top of my to-do list, not by a mile.

"..money than sense.." springs to mind.

Nick

Astro14

The principal advantage, as stated, is that N2 is dry. That's why it's used in aircraft tires. N2 isn't going to make any difference with temperature because (as has been pointed out) it is subject to the universal gas law...

Now, all rubber, even the butyl liners in tires, is slightly permeable. Larger N2 molecules permeate more slowly than smaller O2, but they still pass through the rubber.

The partial pressures of O2 and N2 come into play if you fill the tires with N2. Some amount of N2 will leak out, but (surprisingly if you don't remember this from chemistry) some amount of O2 will leak in until the partial pressure of O2 is in equilibrium across the rubber...so, those who say that their tires don't lose pressure with N2 are simply not measuring over the variations in temperature and are not taking into account the bit of O2 that leaks in...

So, I would save your money. Use dry air (I run my compressor on a nice, dry day) and check/fill your tires often with air...which is 78% N2...you get it for free and works just as well...