Re: First flat in a looooong time

On 4/1/2025 3:02 PM, Jeff Liebermann wrote:

On Wed, 26 Mar 2025 22:01:05 -0400, Joy Beeson
<jbeeson@invalid.net.invalid> wrote:
 

Tuesday, 25 March 2025
>
On Saturday, I came out of Aldi to find my front tire flat.
>
On Monday, I walked to the Trailhouse and handed the wheel
to the mechanic with instructions to put in a new tube and
find out what had happened to the old one.
>
He showed me a crack at the base of the valve stem.   The
tube had died of old age!

 Not old age, but more likely the effects of exposure to chlorine which
can harden and crack rubber.
 Multiple articles on the effects of chlorine on rubber:
<https://www.google.com/search?q=chlorine%20damage%20rubber>
 Thanks to water chlorination, all the rubber seals and faucet gaskets
in my house last about 25 years.  Over the years, I've seen a few
damaged rubber valve stems on cars and bicycles stored near clothes
washing and swimming pool chlorination machinery.  The bleach (sodium
hypochlorite) used in washing condenses on everything and eventually
hardens rubber compounds.
 The good news is that it takes many years for the rubber to harden and
crack.  Viton(FKM) fluorocarbon rubber seals are a big improvement:
<https://www.marcorubber.com/chemical-compatibility/BLEACH%20SOLUTIONS>
I have NOT found any bicycle inner tubes or valve stems made from
Viton(FKM):
<https://www.google.com/search?q=%22Viton%22%20bicycle%20tire%20valve%20stems>
However, one can buy blue Viton (FKM) valve cores for about $2/ea:
<https://schrader-pacific.com/wp-content/uploads/Valve-Core.pdf>
 

While I don't doubt you regarding chlorine (and both ozone and UV also degrade the rubber in our tires/tubes), the base of a bicycle tube valve has absolutely minimal exposure.  A mechanical cause (abrasion, rim liner issues, low pressure) is much more probable.
--
Andrew Muzi
am@yellowjersey.org
Open every day since 1 April, 1971