Re: The AI specified bicycle features of the future

On Mon, 27 May 2024 19:01:13 GMT, Tom Kunich <cyclintom@yahoo.com>
wrote:

On Mon May 27 09:58:39 2024 Jeff Liebermann  wrote:

On Mon, 27 May 2024 10:32:50 -0400, Frank Krygowski
<frkrygow@sbcglobal.net> wrote:
 

On 5/26/2024 9:03 PM, Jeff Liebermann wrote:

 
I'm still not sure.  I hadn't considered the possibility that the
bicycle was not intended to be ridden.  If that's the case, the tires
or tubes could be filled with urethane foam or something similar.

>
In long ago discussions in this forum, there was mention of the problem
of pneumatic tires on museum bicycles deflating over time. Supposedly,
one solution is to "inflate" them with water instead of air.

 
That works if the tube doesn't also leak water.  For vintage wheels,
the rim and spokes will likely be steel, which will eventually rust.
The water might also leak.  I don't think the museum would tolerate a
water puddle under each tire.  Methinks soft expanding urethane foam
would be a suitable leak and rust proof alternative to water:
<https://www.google.com/search?q=soft+urethane+expanding+foam+&tbm=isch>
The result is a closed cell foam sponge that might possibly be
rideable.  I've never tried it.

When you don't know anything about bicycles why do you continue to comment on them?

Because my corrections to your mistakes are entertaining to me and
irritating to you.

Tubes leak air because the air molecules are smnaller than the
pores in the rubber. They do not leak water because the water
molecules are larger than the pores.

Wrong.  The kinetic diameter of the nitrogen (N2) molecule, the major
component of air, is 0.364 nanometers, while the water (H2O) molecule
is 0.265 nanometers.  It would seem that water can diffuse through the
approximately 1.2 nanometer diameter pores in a butyl rubber membrane
more easily than nitrogen gas:
<https://en.wikipedia.org/wiki/Kinetic_diameter>
<https://www.applerubber.com/hot-topics-for-engineers/the-permeability-of-rubber-compounds/>

It might seem like more air passes through a pore or hole because it
has the approximately 50 psi tire pressure behind it to force the air
through.  That's not a valid comparison.  A bicycle tube full of water
has only the weight of the circular water column to push it through
the hole.  However, if I fill the lower half of the inner tube with
water and then fill the upper half with 50 psi air, the water will
leak through somewhat faster than air.

Another reason that air seems to leak through a rubber membrane, while
water does not, is the rubber membranes used for containing air are
very thin, while the rubber membranes used to containing water are
much thicker.  It might be fun to build a garden hose from old bicycle
inner tubes spliced together and watch what happens when you turn on
the water.  (My water pressure from the garden hose bib is about 60
psi). 


--
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558