Re: Very Slow Leaks.

On Tue, 6 May 2025 15:21:46 -0400, Zen Cycle <funkmaster@hotmail.com>
wrote:

On 5/6/2025 2:05 PM, Jeff Liebermann wrote:

On Tue, 6 May 2025 12:47:56 -0500, AMuzi <am@yellowjersey.org> wrote:
 

On 5/6/2025 12:42 PM, Jeff Liebermann wrote:

On Tue, 06 May 2025 10:19:59 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:
>

I once bought some inner tubes that seem to have come from the factory
with leaks. (...)

>
A bit more.  I didn't have enough patches handy, so I used a small
blob of automotive "gasket maker" to plug the hole.
<https://www.permatex.com/products/gasketing/black-gasket-makers/permatex-ultra-black-rtv-silicone-gasket-maker-5-oz/>
I didn't ride enough to determine how many months or miles the black
goo was going to last, but it seems like it would work on small pin
holes.  I don't recommend it for large punctures, long cuts or cracks.
>
Also, I had some slow leaks that were difficult to find using soapy
water.  (At the time, I didn't think to try the ultrasonic leak
detector).  So, I over-inflated the inner tube.  I think it's probably
26 x 1 3/8:
<https://www.learnbydestroying.com/jeffl/crud/inflated-tube.jpg>
Not only did the soapy water detect the leaks, I could hear the air
leak and also feel the air with my fingers.  Also, the normal size of
the tire is the mounted tire located behind the over-inflated tire.
>
If I ever get around to buying a IR camera, I could try heating the
over-inflated tube, and possibly see the air leak because of the
temperature difference.
>

Your image shows a typical inflation for tracking down a
leak. Not overly large at all.

 
I was worried about the excessive stretching of the inner tube causing
the pin-hole to turn into a tear.

>
In the many decades I've been repairing tires, I can honestly say I've
never had that happen when inflating a tube well beyond the rated max
diameter to find a leak.

I have, but not with a bicycle inner tube.  In the early 1960's, the
family and friends would routinely visit either Lake Arrowhead or Big
Bear Lake in the San Bernardino mountains.  Standard equipment
included several large truck size inner tubes for floatation.  Most of
the inner tubes had at least 5 patches.  The inflator was set to
cutoff at about 60 psi.  I kept adding more and more air, waiting for
the compressor to shut off.  It didn't.  Instead, there was a modest
bang followed by the inner tube bouncing around the gas station.  Upon
inspection, the angry gas station owner found a slit on the inner
tube.  I don't recall the exact size of the slit but I think it about
1.5 inches.  I don't recall the exact location of the slit, but do
remember that it did NOT involve one of the patches.

Roll forward a few years (1966?), and I was working after school for a
gas station that sold tires.  I received some instructions on tire
filling but over-inflation was only mentioned in reference to looking
for air leaks.  I hated tires with inner tubes because they were
almost impossible to balance properly.

That won't happen if the tire is in
place because the tire prevents the inner tube from stretching too
much.  However, I didn't know how the tube would react and didn't want
to find out the hard way.
 

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