[s-cars] Everything You Always Wanted to Know About Nitrogen, But Were Afraid to Ask

[Vincent Frégeac]

Surprisingly I got about 50Kmiles on the two sets of Kuhmo 712 I had, a bit
over 30Kmiles from the Yoks I tried.

Now, I'd think someone filing his tires with nitrogen will think, based on
the false advertising, that he will never have to top the pressure again,
which is not the case.

For the bottles of nitrogen, it's not that bad. Small sizes, like 10 or
20lb, are foolproof, the same as propane bottles, and I'd rather have a leak
of nitrogen than propane. Industrial size bottles, 100lb and more, are
another story.



Vincent

-----Message d'origine-----
De : Steve Marinello [mailto:smarinello at entouch.net] 
Envoyé : 21 novembre 2007 13:35
À : Vincent Frégeac
Cc : S List
Objet : Re: [s-cars] Everything You Always Wanted to Know About Nitrogen,
But Were Afraid to Ask

Very nicely compiled, but do you actually get 30k-50k miles on your 
performance tires?  I think these Bridgestones will be toast by 15k.  
Even less of a potential impact.  Now, let's just assume that it's still 
worth it to use Nitrogen for someone.  Are they looking to keep a bottle 
of pressurized gas in their garage to adjust/add gas to raise the 
pressure back to spec?  There's one thing I definitely don't want in my 
garage...unless I've got welding gas bottles already.  Anyone else ever 
see a high pressure bottle of N2 take off after falling and knocking the 
head off?  Not pretty.  Looks just like an airborne torpedo.  At least a 
steel reinforced wall stopped the one I saw...after it had punched half 
way through.   And God forbid your garage catches fire...  Way too 
little advantage for the potential risk for me.

Steve

Vincent Frégeac wrote:
> Hi All,
>
> Since I had to dig into the Nitrogen in tires debate for my work, I
thought
> I could as well share my findings with you. So, here are some facts:
>
> The FAA requires Nitrogen in Tires: TRUE
> - After a plan crash, caused by a burning tire igniting a fuel line when
the
> landgear was retracted, the FAA conducted studies that concluded that the
> time the tire burnt after the landgear was retracted would have been
> noticeably reduced if the tire would have been filled with Nitrogen, since
> this would have reduced signigficantly the volume of oxygen around the
tire.
> Conclusion for us: Except if you have upgraded your car with Mr. Fusion
> engine and retractable wheels ala Back to the Future, you shouldn't care
> about the time your tires will burn when your urS landgear are retracted.
>
> The race cars benefit from Nitrogen in Tires: TRUE and FALSE
> - The pressure in a race car tire will increase by up to 50% due to the
> temperature. Predicting the increase in pressure is very important to
> racers, so they want the same pressure to temperature correlation in every
> tire they use in a race, whenever they have been filled. By filling a tire
> with bottled gaz, they are sure to have the exact same gaz in their tire,
> while outside air has a different humidity content when it's sunny and dry
> than when it's pouring rain. On the other hand, they could achieve this
> reproductibility with any dried bottled gaz, including air. The advantage
of
> nitrogen is it's the cheapest readily available bottled gaz with controled
> content. Now, you can think that you're racing your car too, but a typical
> car tire will increase it's pressure up to 10% when driven normally, up to
> 20% when driven hard, which mean that a 1psi difference in a F1 tire will
> become a 0.4 psi in your tire when driving hard. Beside, you are not
> changing your tires every few hours, just adding some air once a month,
let
> say, worse case scenario adding 5% of air (If you're adding more, you have
a
> slow leak and should do something to it). So, if this 5% of air is 100%
> different than the air of last month, you will experience a difference of
5%
> of 0.4psi when you're driving hard, aka 0.08psi. Now, if you're able to
tell
> by the way your car handle that your LR tire is at 33.48psi after the 3rd
> corner after your home when last month it was at 33.40psi only, and this
> difference in handling really annoys you, you should go with Nitrogen, but
> for all of us who don't have a bionic seat of pants, F1 cars using it is
not
> a good reason to go nitrogen.
>
> Nitrogen keep it's pressure over time: FALSE
> A Consumer Report studies have compared leakage of 20 new tires when
filled
> with air an Nitrogen. The psi drop was anywhere from 1 to 8 psi over a
> period of 1 year, depending on the tire. The difference between air and
> nitrogen was between 0.2 to 1 psi. Now, this study was done with tires
left
> on a rack, so we cannot say the absolute psi drop would be the same when
> driving. However, we can expect the ratio to be the same, which is
nitrogen
> filled tire will loose pressure at 80% of the rate of air filled tire.
> That's better, but they still loose pressure. The difference of pressure
> drop is 20% when switching from air to Nitrogen but up to 800% when
> switching from one tire brand to another. So, first conclusion, choosing
the
> right tire is much more important than choosing the right gaz, and we all
> know we choose our tire because of their handling, their fatness, their
cool
> factor, any reason but gaz permeability. Since we don't care about a 800%
> difference in pressure drop over time, why should we care about a 20%
> difference. Second, Nitrogen still leaks at 80% of the rate of air, which
> means than instead of checking your tire pressure every month, you will be
> able to check your pressure every month and a week (in an ideal world with
> no nails, no leaking valve, no leaking mags, no tire monkeys, etc.)
>
> Nitrogen protect wheels: TRUE and FALSE
> Bottled Nitrogen is dry and somewhat inert. It won't promote rust or
> oxidation even over a very long period of time. On the other hand,
> compressed air, with its combination of oxygen and humidty, does a very
good
> job of promoting rust, which can have a visible effect with steel wheels.
> Are you running on steel wheels!!!?!! Beside, IME, steel wheels rust much
> faster on the outside than on the inside (below the tire) so even if the
> nitrogen protect the inside of the wheel, you still have to change the
> wheels because they're all rotten on the outside. Now, oxydation of
> aluminium does exist too. It is much slower and produce a very fine white
> powder, and Nitrogen will also stop aluminium oxydation. But have you ever
> changed your mags because of oxydation of the inner part?
>
> Nitrogen doesn't change pressure with temperature: FALSE
> This is derivated from race cars using nitrogen. The reason they use
> nitrogen is predictability. Bottled nitrogen is standard, so it will
always
> react the same way, but it is still a gas so the pressure is still more or
> less _proportional_ to the temperature in Kelvin. The difference with air
is
> that air contain humidity and humidity will have an influence on the way
> pressure change with temperature. So pressure change won't be predictable.
> But as mentionned earlier, in our car, it means an unpredictability of
> 0.1psi each time we check and adjust the pressure. Do you really care
about
> a difference of 0.1psi in the 2-3psi variation of your tire pressure when
> the tires warm up?
>
> Nitrogen allows a longer life of the tire: TRUE and FALSE
> >From what I have found, this have not been proved on car tires. While
there
> was no side-by-side comparative study for trucks either, some trucking
> company have reported up to a 48% increase in thread life but, more
> important, the possibility to recap the tire up to 5 times instead of 2-3
> times, after they switched from air to nitrogen. So, on truck tires with a
> 250-300Kmiles thread life which are recaped to last over a million miles,
it
> does make a difference. Does it on the 30-50Kmiles high performance tires
we
> use? Still to be proven. Beside, are you recaping your high performance
> tires. I suppose you don't.
>
> Nitrogen gives a better gas mileage: FALSE
> This is a deduction from the fact that nitrogen leaks less but I found no
> comparative study. The deduction come from the fact that Nitrogen leaks
less
> than air, which is somewhat true. As said earlier, over a year, a nitrogen
> filled tire will loose 2.2 psi only when a air filled tire will loose
> 2.7psi (average of 20 tire brands tested). I don't think a
> 0.5 psi difference over a year will make a difference, especially if you
> check your tire pressure every month. Beside, the choice of tire will vary
> this pressure drop from 1.0 psi to 7.8 psi, so the choice of your tire is
> much more important than Nitrogen. Do you consider the air permeability of
> the rubber when you choose your performance tires? I think not. So if you
> don't care about a 800% difference in pressure drop, why should you care
> about a 20% difference?
>
> Of course, this is just what I found. YMMV. Someone on another list has
even
> reported a 3MPG difference when switching from air to Nitrogen (but he
> forgot that he was switching from worn out tires with unknown pressure to
> brand new tires with on-spec pressure at the same time ;-)
>
>
>
> Vincent
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