On Thu, 12 Jun 2008 23:04:30 -0700 (PDT), Ablang <
[email protected]>
wrote:
>Whether you use your bikes every day, or store them for the winter,
>what are the advantages to keeping your bike off the ground (besides
>the obvious of saving room)?
>
>Does it allow your tires to last longer, or perhaps not lose air
>pressure over time?
Dear Ab,
Nope.
The air pressure rises too little to measure with conventional gauges
when each tire supports a load of about ten pounds.
(Look at the normally inflated tires of a bike as they rest on the
ground--not much flattening, is there?)
The gradual loss of air pressure is a matter of the solubility of air
(80% N2, 20% O2) in the butyl or latex rubber. The gases are much more
soluble in natural latex, so tires with those tubes lose air faster.
(CO2 is _much_ more soluble than N2 or O2, which is why flat tires
pumped up with cartridges lose "air" in a few days.)
Tires that have lost pressure and sat for a very long time can be
damaged, but obviously their owners didn't care about them.
Tire deterioration is a common problem in highwheeler restoration.
After more than a century, natural rubber solid tires are not a pretty
sight:
http://www.hochrad.info/hochradseite/hochradteile/hochrad teile reifen.htm
But they'd be just as ugly even if they'd hung from the ceiling.
Cheers,
Carl Fogel
