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tumadre
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have we cured the ultraviolet light problem? or the normal wear issue? or do we have ozone reducing catylists impregnated in the tyre? I think not.
this is just BS
however, the argument that oxygen leaks through the tyre is valid, but prove that it is harmful to the rubber
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S.C. Wack
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You need more than anecdotal evidence on lack of oxygen leakage, you need actual side-by-side comparisons of cold tires periodically. I find it
difficult to so easily call bullshit outright on this without applying anything resembling actual scientific method.
Remember that there is more claimed than seepage, there is also the claim that wear and tear is reduced by eliminating oxidation from the interior.
As for neutrino's doubts as to the competency of Sperberg, I can't say; but Sperberg has probably had more papers published in a journal (2) than
anyone here. What he's done more closely resembles science than the research of others in this thread.
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apidej
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good
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turd
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| Quote: | | You need more than anecdotal evidence on lack of oxygen leakage, you need actual side-by-side comparisons of cold tires periodically.
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No, it's the other way round: extraordinary claims demand extraordinary evidence. And "I've published it" doesn't count as evidence.
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unionised
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"Sperberg has probably had more papers published in a journal (2) than anyone here."
I doubt that.
Anyway, since there are 2 groups of people here; those who believe there may be something in this claim and those who don't. Yet there are, it seems,
none who can be bothered to do the experiment, I don't see this thread progressing.
The observation that, whatever you do to the inside of the tyre, the air will still oxidise the outside is reasonable, but it presuposes that the
rubber is the same on the outside as the inside; I don't think that's true.
My understanding is that people replace tyres because the treads wear out; so whatever happens inside is not going to improve the longevity of the
product.
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S.C. Wack
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That is exactly the problem that I see here. I don't know about the effect on tires and really don't care. What I do know is that those who haven't
done or at least examined experimental work seem unqualified for the job of pronouncing verdicts on subjects that they have no innate insight into. I
would think that chemists would understand, thus my shock. It all seems more unscientific than the claims made; whether true or wishful interpretation
of some published experimental data.
Ohm might understand my point.
If I was given to having an opinion without road testing, I would sooner form an opinion based on what large truck fleets are doing, as their tire
costs are very high; rather than trying to apply some insight into tires that I don't have.
turd, I don't understand your post at all. How is the opposite of needing more than anecdotal evidence helpful in determination of wear? Anecdotal
evidence trumps scientific method? WTF?
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tumadre
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I am NOT convinced that oxygen is in fact harming the tire
look on the inside of any old and cracked up tire, and you will find the inside to be fine.
and another good cause of wear is the steel on rubber interface internal to the tire.
at very high pressures and temps, the O2 might break down the steel-rubber interface (water would help that)
but for automobile applications? there are a lot of people filling tires with N2, I'm suprised auto makers don't recommend it.
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turd
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| Quote: | | turd, I don't understand your post at all. How is the opposite of needing more than anecdotal evidence helpful in determination of wear? Anecdotal
evidence trumps scientific method? WTF? |
My point was: the burden of proof is on the one claiming dubious things. And the more extraordinary the claim, the more extraordinary the evidence
that is needed. So far I'm not convinced at all (not that I care about people wasting their money on N2-inflated tires, homeopathy or whatever).
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unionised
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Does anyone remember that the original website cited said this
"Unlike oxygen molecules, which are so small they leak through tires over time, nitrogen molecules are much larger, so the tires will stay fully
inflated three to four times longer"
That sort of claim needs a hell of a lot of evidence backing it before it begins to contradict many years of scientific knowledge.
I really think that, as a scientist ( A chemist as it happens) I really can call bullshit on that without needing to so much as look at a tyre.
Is there anyone out there who realy thinks oxygen is a lot smaller than nitrogen?
This isn't even bad anecdotal evidence as far as I can see; it's fraud and I think this page from another site cited speaks volumes
http://www.purigen98.com/index.php?page=research
You really can fool some of the people all of the time and some of them will pay for nitrogen filled tyres.
Even the report saying it's worthwhile is a bit understated.
"Nitrogen’s slower permeability characteristics coupled with its bone-dry nature may partially ameliorate some field abuse conditions, including
long term inflation maintenance neglect, improper repairs and certain types of tire pressure monitor malfunctions. Even though high purity nitrogen is
no guarantee of performance and will not undo the many forms of damage or abuse that can lead to tire failure, it offers a low cost, risk free and
positive service opportunity that has finally become commercially and technically practical”.
Let's have alook what that says.
It MAY help defer the problems due to neglect.
The lack of water (which doesn't react much with rubber) is given as one of the advantages.
Nitrogen offers no guarantee of performance.
That's from the bloke paid by the manufacturer of the kit.
The "published" report includes the following
"When a tire lives to wear out, the oxygen slowly migrates and permeates its way into and through the tire cord body and finally into the under tread
and then into the tread itself. It takes a long time for an appreciable amount of oxygen to reach the tread since most of the oxygen gets waylaid
along the way by the liner, and then the cord arid cord insulation compound. "
Why in the name of God does he assume that oxidation is due to air coming from inside the tyre? What's wrong with the air outside it? Doesn't he
realise that there isn't a lot of air in a tyre; but there's plenty of it out here?
Were those "reports" peer reviewed. Are they only published in the sense thet they are on the net?
BTW, "have we cured the ultraviolet light problem? or the normal wear issue? or do we have ozone reducing catylists impregnated in the tyre? I think
not."
Er.. actually, yes; carbon black is used as a filler in tyres, it absorbs UV very well and it also catalyses the decomposition of ozone.
[Edited on 18-9-2006 by unionised]
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S.C. Wack
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You are allowed to search the internet, too. I mentioned on the first page where the available (to members) reports are. They are in rubber industry
journals and the proceedings of ACS Rubber, just last week there were some related papers presented.
There is only one paper (in two versions) available to the public AFAIK, a study of internal oxidation that has little to do with the real world
except in theory:
http://www.getnitrogen.org/pdf/print_articles/Ford%20Baldwin...
At least one (Sperberg, 1968) seems to attempt something of use or at least fakes it, but obviously what is needed is real passenger cars driving real miles,
combined with cost/benefit analysis. No one seems interested in funding such a venture.
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unionised
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Have tyres changed since 1968?
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mick
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An easy experiment to do to check the porosity of rubber could be to inflate a balloon with air and see how long it lasts Inflate a ballon with
nitrogen and see how long it lasts.
My personal experience is that 3 rubber balloons inserted inside each other and filled with argon or nitrogen, the outer balloon will disintergate due
to oxidation.
mick
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Twospoons
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| Quote: | Originally posted by unionised
"Unlike oxygen molecules, which are so small they leak through tires over time, nitrogen molecules are much larger, so the tires will stay fully
inflated three to four times longer"
That sort of claim needs a hell of a lot of evidence backing it before it begins to contradict many years of scientific knowledge.
I really think that, as a scientist ( A chemist as it happens) I really can call bullshit on that without needing to so much as look at a tyre.
Is there anyone out there who realy thinks oxygen is a lot smaller than nitrogen? |
The difference in size may not be much, but the difference in diffusion rates can be considerable. This is how pressure swing adsorption air
separators work. I was looking up physical properties of polyimide yesterday, and amongst the data I was after I noticed that the permeability for
oxygen was over 3 times that of nitrogen ref . For the zeolites used in PSA separators the difference can be 10x, IIRC.
But while there is a potential basis in reality for using N2, $8 a fill is still rather steep - given the rather dubious benefits. What does a tyre
cost over there, anyway? I can get a good tyre here for NZ$125.
Helicopter: "helico" -> spiral, "pter" -> with wings
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unionised
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We use nitrogen generators at work that rely on exactly that effect.
I was just pointing out that the site talked bull.
[Edited on 21-9-2006 by unionised]
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richard
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If the case is true that oxygen is lost, refilling your tyre will gradualy deplete the amount of oxygen any way. Bit silly paying $8 for some thing
which would happen anyway.
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