glueless patches

Alex Rodriguez writes:

I'm now running Conti Travel Contact tyres at 85 PSI (with new
tubes), so I'm patiently waiting for my first puncture to see how
those patches handle the higher pressure.

I got my first puncture on these tyres yesterday. It was from a
stiff "Michelin wire", too fine to measure with my cheap vernier
caliper, so I don't begrudge the Kevlar belts letting it through.

Anyhow, the Park glueless patch I used is still holding up at 85
PSI.

FYI. The park patches I used were on my racing bike that regularly
saw 120psi. That's the patch that held for a year.

Higher pressure generally assures better patch survival if the patch
is not fully cured to the tube (such that you can't peel it off
manually). The softer the tire, the more it flexes. Tire casing flex
is what ultimately loosens glueless patches... or conventional ones
that have just been applied.

The test for this is to lay a paper business card between tube and
casing and observe what is left of the card after about 100 miles.

Jobst Brandt

In article ,
says...
A Muzi wrote:

Yeah, Andy! That's the first time I've heard something I hadn't heard
before about patching tubes in YEARS!

Thanks;
Mark "glad to finally be back on a newsserver" Spoken

We do not generally patch now, but when we did (and _lots_
of them every day) we used a normal "patch buffer" solvent
with a clean cloth. I still clean tubes that way for
patching the odd irreplaceable tube.

When I was young I remember the old guys would smear cement
over the area, wait a moment and scrape it away with a
pocket knife. That was also effective in removing any dirt
and extraneous material from the tube's surface.

I don't see a reason to use an abrasive in a shop when you
have a much more thorough and effective method of cleaning
available. The point is _not_ to texture or smooth the
tube; the point is to clean the surface detritus out of the
way so the glue and patch might adhere to the tube itself,
not the crud layer over it.

Pete Biggs wrote:
Can solvent alone remove the mold release*?

* http://draco.acs.uci.edu/rbfaq/FAQ/8b.1.html


Yes, certainly, along with any other wax, oil, grease and
dirt. Look at the color of the cloth after you rub solvent
across the injury. Much of that crud would still be there
had you used a sandpaper.

Adam Rush wrote:
The longer a duration without flats you talk about on r.b.t, the
higher the chances of that nasty goathead deflowering your wheel's
butyl undergarments.

I flatted on Christmas Day AGAIN. It's starting to get to me...
--
David Damerell flcl?

I'm a relatively recent convert. I've probably used about half a dozen, and
have had one go wonky. I put this down to user error as all the others have
been absolutely fine - on both road bikes and MTBs.

All the best, Trevor