Re: Tires Gradually Go Flat in Storage

Michael Press wrote:
In article <msydneBIgJjl5bXanZ2dnUVZ_sbinZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:

Michael Press wrote:
In article <EoKdncjNYqwRm7XanZ2dnUVZ_oCvnZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:

Michael Press wrote:
In article <Ptmdnb7hmZyJZrranZ2dnUVZ_s7inZ2d@xxxxxxxxxxxxx>,
jim beam <spamvortex@xxxxxxxxxxxxxxx> wrote:

Michael Press wrote:
In article <47265218$0$14128$742ec2ed@xxxxxxxxxxxxxx>,
jobst.brandt@xxxxxxxxxxxxxxxxxx wrote:

Someone writes:

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 are less
corrosion on tubeless tire wheels due to absence of water vapor
and oxygen.
I am surprised that no one has offered helium tire inflation to the
weight-weenie crowd.
Some pro/national track teams use helium in their tubulars, but the
very small molecule (actually just an atom) combined with latex
tubes means pressure loss is too fast to make this practical for
road bikes used for several hours at a time.
It has been alleged that the GB track team use much cheaper
nitrogen, but paint their nitrogen cylinders to make other teams
think they're using helium.
Hydrogen, although a diatomic element is leakier than helium, a
montomic molecule.

2 He, 10 Ne, 18 Ar, 36 Kr, 54 Xe, 86 Rn
What is called for is the molecular mass not atomic mass.
MM is what governs the diffusion rate.

He 4.003
Ne 20.18
Ar 39.95
Kr 83.80
Xe 131.3 Ra 226

(Do not worry about the decimal places.)
Molecular mass of H2 is 2. This gives He a diffusion rate 0.7 times
that of H2.
yeahbut, the molecular size of H2 is much larger than the atomic size of He. that also affects diffusion rate.
How big is the H2 molecule,
http://en.wikipedia.org/wiki/Molecule#Molecular_size

and how big is the He atom?
http://en.wikipedia.org/wiki/Helium
So, how big are they?
what's the problem michael? wikipedia/google/the world's library of chem text books not working for you? or do you have some other agenda? if the latter, quit fucking about and say what's on your mind.

You claim that the H2 molecule is much larger than
the He atom. I asked how big they are. How big are they?
It seems that it is you, not I, who is temporizing.


eh? i'm "claiming" what you yourself can read in a host of scientific texts. if you think you can contradict published science data, go right ahead!
.