Tires Gradually Go Flat in Storage

[[email protected]]

Tom Sherman writes:

>>>>> By the way, moist air is lighter than dry air.

>>>> So if you don't have hydrogen or helium available, always fill
>>>> your tires on a humid day.

>>> Better still - just _fill_ the suckers with water. Provides a nice
>>> hard ride with the added benefit of being able to find leaks
>>> instantly by observing the spurt of water squirting out through
>>> the smallest of pin-hole.

>> Not to laugh, filling a tire with water works well and isn't as
>> hard as you think. The only problem is that the tire is heavier.
>> If you have a slow leak and nothing with which to fix it on the
>> road, fill the tire with water. I've done it and it works like a
>> charm. Of course you have to have a good frame fit pump (long
>> stroke Silca) that can be filled with water. Make sure to let out
>> all remaining air so the water doesn't slosh around.

> I thought Jobst preferred milk to water? See:

http://groups.google.com/group/rec.bicycles.tech/msg/c1a9f571ffd02438?dmode=source

That's a different problem and it only takes a small shot of whole
milk *with fat) to work as a slow leak plugger. The water (board)
fill is a different event.

Jobst Brandt

 

[Ben C]

On 2007-11-01, Ben C <[email protected]> wrote:
[...]
> A picometre is 4e-11 inches. So that's 1/100000000000th of an inch.

Sorry-- 4/100000000000th of an inch (approximately).

 

[[email protected]]

On Thu, 01 Nov 2007 04:44:55 -0500, Ben C <[email protected]> wrote:

>On 2007-11-01, jim beam <[email protected]> wrote:
>> Michael Press wrote:
>[...]
>>> What are the sizes? What is "much larger"?
>>>
>>
>> what's the matter michael? is your web browser broken?
>
>According to http://en.wikipedia.org/wiki/Molecule#Molecular_size, H2 is
>the smallest diatomic molecule and is roughly 1.48 Angstroms in length.
>That's about 0.15nm.
>
>As for a Helium atom, this page:
>http://zebu.uoregon.edu/~soper/Sun/step0.html says it's 10-10m, which is
>0.1nm.
>
>So not much difference in size at all.

Dear Ben,

The size of the molecules is as irrelevant as the quibbling.

The larger CO2 molecule escapes through butyl rubber at about ten
times the rate of the obviously smaller O2 molecule:


http://www2.dupont.com/Vamac/en_US/assets/downloads/vamac_gas_permeability.pdf

You can find some explanations here:

http://www.soarnol.com/eng/solution/solution060313.html

Cheers,

Carl Fogel

 

[A Muzi]

> "Michael Press" wrote: (clip)Publish the numbers and
>> cite your references as others do.

Leo Lichtman wrote:
> A hydrogen atom consists of one proton in the nucleus, with one electron
> orbiting around it. A hydrogen molecule consists of a pair of hydrogen
> atoms which complete their electron shells by sharing their electrons. A
> helium atom consists of a nucleus with two protons, and two electrons
> orbiting around it. Thus, they have the same molecular weight, but the
> hydrogen molecule is approximately twice as large, because the protons are
> not together in the same nucleus. The actual sizes do not need to be known
> for this to be understood.

Thanks for a clear explanation.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Peter Cole]

Michael Press wrote:
> In article
> <[email protected]>,
> Matt O'Toole <[email protected]> wrote:
>
>> On Sun, 28 Oct 2007 10:07:54 -0400, William Bikash wrote:
>>
>>> Has anybody tried filling bicycle tires with nitrogen? Auto tire
>>> dealers are offering a nitrogen fill option claiming less leakdown due
>>> to the larger molecules.Also less pressure variation ane less corrosion
>>> on tubeless tire wheels due to absence of water vapor and oxygen.
>> It's true, and it's why car and truck air shocks and tires are filled
>> with nitrogen at the factory. Not everyone uses nitrogen for tires, but
>> some carmakers do, and their dealers as well.
>>
>> I have no idea how much less a tire will leak when filled with nitrogen
>> though. Anyone with a nitrogen tank (such as for welding) want to
>> experiment?
>
> I do not have accurate numbers. I inflate my tires to
> 115-120 psi with N2. After about three weeks they are
> about 90 psi. As far as I know there is no difference
> from pumping atmosphere into tires.
>

From:

http://www.dowcorning.com/content/rubber/rubberprop/rubber_perm.asp

permeability of butyl rubber:

N2 = 0.025

O2 = 0.098

Air = 0.02 (rounding?)

 

[A Muzi]

Ben C wrote:
> On 2007-11-01, Ben C <[email protected]> wrote:
> [...]
>> A picometre is 4e-11 inches. So that's 1/100000000000th of an inch.
> Sorry-- 4/100000000000th of an inch (approximately).

I found Leo's comments quite helpful. We humans are good with half an
inch or a quarter of one, even a tenth. But -11 exponent is not easy to
visualize if one doesn't work in that scale commonly.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Michael Press]

In article
<[email protected]>,
[email protected] wrote:

> On Thu, 01 Nov 2007 04:44:55 -0500, Ben C <[email protected]> wrote:
>
> >On 2007-11-01, jim beam <[email protected]> wrote:
> >> Michael Press wrote:
> >[...]
> >>> What are the sizes? What is "much larger"?
> >>>
> >>
> >> what's the matter michael? is your web browser broken?
> >
> >According to http://en.wikipedia.org/wiki/Molecule#Molecular_size, H2 is
> >the smallest diatomic molecule and is roughly 1.48 Angstroms in length.
> >That's about 0.15nm.
> >
> >As for a Helium atom, this page:
> >http://zebu.uoregon.edu/~soper/Sun/step0.html says it's 10-10m, which is
> >0.1nm.
> >
> >So not much difference in size at all.
>
> Dear Ben,
>
> The size of the molecules is as irrelevant as the quibbling.
>
> The larger CO2 molecule escapes through butyl rubber at about ten
> times the rate of the obviously smaller O2 molecule:

What are the transfer rates through butyl rubber at various
pressures < 8 bar for

1) H2
2) He
3) CO2

?

--
Michael Press

 

[Michael Press]

In article
<[email protected]>,
Peter Cole <[email protected]> wrote:

> Michael Press wrote:
> > In article
> > <[email protected]>,
> > Matt O'Toole <[email protected]> wrote:
> >
> >> On Sun, 28 Oct 2007 10:07:54 -0400, William Bikash wrote:
> >>
> >>> Has anybody tried filling bicycle tires with nitrogen? Auto tire
> >>> dealers are offering a nitrogen fill option claiming less leakdown due
> >>> to the larger molecules.Also less pressure variation ane less corrosion
> >>> on tubeless tire wheels due to absence of water vapor and oxygen.
> >> It's true, and it's why car and truck air shocks and tires are filled
> >> with nitrogen at the factory. Not everyone uses nitrogen for tires, but
> >> some carmakers do, and their dealers as well.
> >>
> >> I have no idea how much less a tire will leak when filled with nitrogen
> >> though. Anyone with a nitrogen tank (such as for welding) want to
> >> experiment?
> >
> > I do not have accurate numbers. I inflate my tires to
> > 115-120 psi with N2. After about three weeks they are
> > about 90 psi. As far as I know there is no difference
> > from pumping atmosphere into tires.
> >
>
> From:
>
> http://www.dowcorning.com/content/rubber/rubberprop/rubber_perm.asp
>
> permeability of butyl rubber:
>
> N2 = 0.025
>
> O2 = 0.098
>
> Air = 0.02 (rounding?)

Thanks. This is measurable, but I am not capable of noticing
the difference.

Another interesting effect is the leaking of O2 _into_
a tube inflated with pure N2. This will increase the
time that a tire remains inflated above a set value, p,
when inflated above p.

--
Michael Press

 

[Ben C]

On 2007-11-01, Michael Press <[email protected]> wrote:
> In article
><[email protected]>,
> Peter Cole <[email protected]> wrote:
[...]
>> http://www.dowcorning.com/content/rubber/rubberprop/rubber_perm.asp
>>
>> permeability of butyl rubber:
>>
>> N2 = 0.025
>>
>> O2 = 0.098
>>
>> Air = 0.02 (rounding?)
>
> Thanks. This is measurable, but I am not capable of noticing
> the difference.
>
> Another interesting effect is the leaking of O2 _into_
> a tube inflated with pure N2. This will increase the
> time that a tire remains inflated above a set value, p,
> when inflated above p.

That is an interesting effect. Since the tyre is more permeable to O2
than to N2, could it actually reach a higher pressure than what you
originally pumped it up to?

 

[Michael Press]

In article
<[email protected]>,
Ben C <[email protected]> wrote:

> On 2007-11-01, Michael Press <[email protected]> wrote:
> > In article
> ><[email protected]>,
> > Peter Cole <[email protected]> wrote:
> [...]
> >> http://www.dowcorning.com/content/rubber/rubberprop/rubber_perm.asp
> >>
> >> permeability of butyl rubber:
> >>
> >> N2 = 0.025
> >>
> >> O2 = 0.098
> >>
> >> Air = 0.02 (rounding?)
> >
> > Thanks. This is measurable, but I am not capable of noticing
> > the difference.
> >
> > Another interesting effect is the leaking of O2 _into_
> > a tube inflated with pure N2. This will increase the
> > time that a tire remains inflated above a set value, p,
> > when inflated above p.
>
> That is an interesting effect. Since the tyre is more permeable to O2
> than to N2, could it actually reach a higher pressure than what you
> originally pumped it up to?

Unlikely. I have not done the arithmetic.
The O2 wants in with 1/5 bar behind it.
The N2 wants out with 8 bar behind it.

--
Michael Press

 

[[email protected]]

On Thu, 01 Nov 2007 22:41:48 GMT, Michael Press <[email protected]>
wrote:

>In article
><[email protected]>,
> [email protected] wrote:
>
>> On Thu, 01 Nov 2007 04:44:55 -0500, Ben C <[email protected]> wrote:
>>
>> >On 2007-11-01, jim beam <[email protected]> wrote:
>> >> Michael Press wrote:
>> >[...]
>> >>> What are the sizes? What is "much larger"?
>> >>>
>> >>
>> >> what's the matter michael? is your web browser broken?
>> >
>> >According to http://en.wikipedia.org/wiki/Molecule#Molecular_size, H2 is
>> >the smallest diatomic molecule and is roughly 1.48 Angstroms in length.
>> >That's about 0.15nm.
>> >
>> >As for a Helium atom, this page:
>> >http://zebu.uoregon.edu/~soper/Sun/step0.html says it's 10-10m, which is
>> >0.1nm.
>> >
>> >So not much difference in size at all.
>>
>> Dear Ben,
>>
>> The size of the molecules is as irrelevant as the quibbling.
>>
>> The larger CO2 molecule escapes through butyl rubber at about ten
>> times the rate of the obviously smaller O2 molecule:
>
>What are the transfer rates through butyl rubber at various
>pressures < 8 bar for
>
>1) H2
>2) He
>3) CO2

Dear Michael,

Why not look up the answers and tell us something?

The links have been posted several times.

Cheers,

Carl Fogel

 

[Tom Sherman]

"jim beam" wrote:
> ...
> "is this the right room for an argument?"
> "i've told you once!"
> "no you haven't!"
> "yes i have!"
> [etc]

Oh! I'm sorry, this is abuse.

--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?

 

[Tom Sherman]

Andrew Muzi mused:
> Ben C wrote:
>> On 2007-11-01, Ben C <[email protected]> wrote:
>> [...]
>>> A picometre is 4e-11 inches. So that's 1/100000000000th of an inch.
>> Sorry-- 4/100000000000th of an inch (approximately).
>
> I found Leo's comments quite helpful. We humans are good with half an
> inch or a quarter of one, even a tenth. But -11 exponent is not easy to
> visualize if one doesn't work in that scale commonly.

I suspect that Andrew would be very good at visually estimating the
sizes of threaded fasteners.

--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?

 

[Tom Sherman]

Peter Cole wrote:
> Michael Press wrote:
>> In article <[email protected]>,
>> Matt O'Toole <[email protected]> wrote:
>>
>>> On Sun, 28 Oct 2007 10:07:54 -0400, William Bikash wrote:
>>>
>>>> Has anybody tried filling bicycle tires with nitrogen? Auto tire
>>>> dealers are offering a nitrogen fill option claiming less leakdown due
>>>> to the larger molecules.Also less pressure variation ane less corrosion
>>>> on tubeless tire wheels due to absence of water vapor and oxygen.
>>> It's true, and it's why car and truck air shocks and tires are filled
>>> with nitrogen at the factory. Not everyone uses nitrogen for tires, but
>>> some carmakers do, and their dealers as well.
>>>
>>> I have no idea how much less a tire will leak when filled with nitrogen
>>> though. Anyone with a nitrogen tank (such as for welding) want to
>>> experiment?
>>
>> I do not have accurate numbers. I inflate my tires to
>> 115-120 psi with N2. After about three weeks they are
>> about 90 psi. As far as I know there is no difference
>> from pumping atmosphere into tires.
>>
>
> From:
>
> http://www.dowcorning.com/content/rubber/rubberprop/rubber_perm.asp
>
> permeability of butyl rubber:
>
> N2 = 0.025
>
> O2 = 0.098
>
> Air = 0.02 (rounding?)
>
Interesting how much more permeable natural rubber is than butyl rubber.
No wonder latex tubes hold air so poorly.

--
Tom Sherman - Holstein-Friesland Bovinia
When did ignorance of biology become a "family value"?

 

[Bill Sornson]

Tom Sherman wrote:

> In the frozen land of Nador, they were forced to eat Robin's
> minstrels.
> And there was much rejoicing.

But alas, no trimming.

 

[[email protected]]

Leo Lichtman writes:

> A hydrogen atom consists of one proton in the nucleus, with one
> electron orbiting around it. A hydrogen molecule consists of a pair
> of hydrogen atoms which complete their electron shells by sharing
> their electrons. A helium atom consists of a nucleus with two
> protons, and two electrons orbiting around it. Thus, they have the
> same molecular weight, but the hydrogen molecule is approximately
> twice as large, because the protons are not together in the same
> nucleus. The actual sizes do not need to be known for this to be
> understood.

So what affects diffusion through an inner tube if it isn't given by
these parameters?

It has been my experience that in the days of latex tubes in Clement
tubular tires, cold weather allowed us to ride two days instead of
one after pumping to about 100psi on a bicycle tour.

Jobst Brandt

 

[datakoll]

less squeezing from frozen rubbah?

 

[Michael Press]

In article
<[email protected]>,
[email protected] wrote:

> On Thu, 01 Nov 2007 22:41:48 GMT, Michael Press <[email protected]>
> wrote:
>
> >In article
> ><[email protected]>,
> > [email protected] wrote:
> >
> >> On Thu, 01 Nov 2007 04:44:55 -0500, Ben C <[email protected]> wrote:
> >>
> >> >On 2007-11-01, jim beam <[email protected]> wrote:
> >> >> Michael Press wrote:
> >> >[...]
> >> >>> What are the sizes? What is "much larger"?
> >> >>>
> >> >>
> >> >> what's the matter michael? is your web browser broken?
> >> >
> >> >According to http://en.wikipedia.org/wiki/Molecule#Molecular_size, H2 is
> >> >the smallest diatomic molecule and is roughly 1.48 Angstroms in length.
> >> >That's about 0.15nm.
> >> >
> >> >As for a Helium atom, this page:
> >> >http://zebu.uoregon.edu/~soper/Sun/step0.html says it's 10-10m, which is
> >> >0.1nm.
> >> >
> >> >So not much difference in size at all.
> >>
> >> Dear Ben,
> >>
> >> The size of the molecules is as irrelevant as the quibbling.
> >>
> >> The larger CO2 molecule escapes through butyl rubber at about ten
> >> times the rate of the obviously smaller O2 molecule:
> >
> >What are the transfer rates through butyl rubber at various
> >pressures < 8 bar for
> >
> >1) H2
> >2) He
> >3) CO2
>
> Why not look up the answers and tell us something?

It is your proposition. I am not here to do
your work for you.

> The links have been posted several times.

The discussion had been about H2 and He.
You brought the transport rate of CO2.
I propose that you provide the data.
You and jim beam want others to do
your and jim beam's research.
You have a proposition? Prove it.

What are the transfer rates through butyl rubber at various
pressures < 8 bar for
1) H2
2) He
3) CO2

--
Michael Press

 

[[email protected]]

On Fri, 02 Nov 2007 03:31:42 GMT, Michael Press <[email protected]>
wrote:

>In article
><[email protected]>,
> [email protected] wrote:
>
>> On Thu, 01 Nov 2007 22:41:48 GMT, Michael Press <[email protected]>
>> wrote:
>>
>> >In article
>> ><[email protected]>,
>> > [email protected] wrote:
>> >
>> >> On Thu, 01 Nov 2007 04:44:55 -0500, Ben C <[email protected]> wrote:
>> >>
>> >> >On 2007-11-01, jim beam <[email protected]> wrote:
>> >> >> Michael Press wrote:
>> >> >[...]
>> >> >>> What are the sizes? What is "much larger"?
>> >> >>>
>> >> >>
>> >> >> what's the matter michael? is your web browser broken?
>> >> >
>> >> >According to http://en.wikipedia.org/wiki/Molecule#Molecular_size, H2 is
>> >> >the smallest diatomic molecule and is roughly 1.48 Angstroms in length.
>> >> >That's about 0.15nm.
>> >> >
>> >> >As for a Helium atom, this page:
>> >> >http://zebu.uoregon.edu/~soper/Sun/step0.html says it's 10-10m, which is
>> >> >0.1nm.
>> >> >
>> >> >So not much difference in size at all.
>> >>
>> >> Dear Ben,
>> >>
>> >> The size of the molecules is as irrelevant as the quibbling.
>> >>
>> >> The larger CO2 molecule escapes through butyl rubber at about ten
>> >> times the rate of the obviously smaller O2 molecule:
>> >
>> >What are the transfer rates through butyl rubber at various
>> >pressures < 8 bar for
>> >
>> >1) H2
>> >2) He
>> >3) CO2
>>
>> Why not look up the answers and tell us something?
>
>It is your proposition. I am not here to do
>your work for you.
>
>> The links have been posted several times.
>
>The discussion had been about H2 and He.
>You brought the transport rate of CO2.
>I propose that you provide the data.
>You and jim beam want others to do
>your and jim beam's research.
>You have a proposition? Prove it.
>
>What are the transfer rates through butyl rubber at various
>pressures < 8 bar for
>1) H2
>2) He
>3) CO2

Dear Michael,

Er, no, you haven't kept up with the discussion from the beginning, so
you hijacked it off-topic.

Look it up yourself--it would be a refreshing change for you to supply
something.

Cheers,

Carl Fogel

 

[Michael Press]

In article
<[email protected]>,
[email protected] wrote:

> On Fri, 02 Nov 2007 03:31:42 GMT, Michael Press <[email protected]>
> wrote:
>
> >In article
> ><[email protected]>,
> > [email protected] wrote:
> >
> >> On Thu, 01 Nov 2007 22:41:48 GMT, Michael Press <[email protected]>
> >> wrote:
> >>
> >> >In article
> >> ><[email protected]>,
> >> > [email protected] wrote:
> >> >
> >> >> On Thu, 01 Nov 2007 04:44:55 -0500, Ben C <[email protected]> wrote:
> >> >>
> >> >> >On 2007-11-01, jim beam <[email protected]> wrote:
> >> >> >> Michael Press wrote:
> >> >> >[...]
> >> >> >>> What are the sizes? What is "much larger"?
> >> >> >>>
> >> >> >>
> >> >> >> what's the matter michael? is your web browser broken?
> >> >> >
> >> >> >According to http://en.wikipedia.org/wiki/Molecule#Molecular_size, H2 is
> >> >> >the smallest diatomic molecule and is roughly 1.48 Angstroms in length.
> >> >> >That's about 0.15nm.
> >> >> >
> >> >> >As for a Helium atom, this page:
> >> >> >http://zebu.uoregon.edu/~soper/Sun/step0.html says it's 10-10m, which is
> >> >> >0.1nm.
> >> >> >
> >> >> >So not much difference in size at all.
> >> >>
> >> >> Dear Ben,
> >> >>
> >> >> The size of the molecules is as irrelevant as the quibbling.
> >> >>
> >> >> The larger CO2 molecule escapes through butyl rubber at about ten
> >> >> times the rate of the obviously smaller O2 molecule:
> >> >
> >> >What are the transfer rates through butyl rubber at various
> >> >pressures < 8 bar for
> >> >
> >> >1) H2
> >> >2) He
> >> >3) CO2
> >>
> >> Why not look up the answers and tell us something?
> >
> >It is your proposition. I am not here to do
> >your work for you.
> >
> >> The links have been posted several times.
> >
> >The discussion had been about H2 and He.
> >You brought the transport rate of CO2.
> >I propose that you provide the data.
> >You and jim beam want others to do
> >your and jim beam's research.
> >You have a proposition? Prove it.
> >
> >What are the transfer rates through butyl rubber at various
> >pressures < 8 bar for
> >1) H2
> >2) He
> >3) CO2
>
> Er, no, you haven't kept up with the discussion from the beginning, so
> you hijacked it off-topic.
>
> Look it up yourself--it would be a refreshing change for you to supply
> something.

You brought in the mobility of CO2 in a sub-thread
on the size of H2 and He. So you have diverted a
discussion as much as I. As for my initial post
it was to correct Jobst Brandt using atomic number
in a context of diffusion coefficients, where
molecular mass is the parameter of interest.

As you say, there is more than size involved.
You intervened in a discussion of H2 and He
to bring in CO2. Now contrast CO2 with H2 and He.

--
Michael Press