On Thursday, April 8, 2021 at 7:00:17 AM UTC-7, AMuzi wrote:
On 4/8/2021 7:43 AM, Tom Kunich wrote:
On Wednesday, April 7, 2021 at 1:47:35 PM UTC-7, wrote:
On Tue, 6 Apr 2021 21:09:12 -0700 (PDT), jbeattie
wrote:
A few miles into my evening ride on my
cable-shift Emonda -- with my wife pushing me
on her ebike, I shifted to go up the next hill
and snap -- immediate downshift into 34/11.
(...)

There used to be a company selling carbon fiber brake cable kits
called Power Cordz:
https://www.velonews.com/gear/road-gear/wrenched-and-ridden-power-cordz-brake-and-shifter-cables/
Their web site at:
http://www.powercordz.com
is gone, so I assume that something went wrong with the company or
product. Seems to be a tolerable alternative.
https://forums.thepaceline.net/showthread.php?t=254169
https://www.pinkbike.com/news/power-cordz-review-2010.html
https://www.roadbikerider.com/power-cordz-d1/

If you don't mind risking your bicycle, life, and future, you can
possibly replace the steel brake wire with a different material, such
as carbon fiber or various Aramid fibers such as Kevlar, Dyneema,
Spectra Amsteel Blue, etc. However, if the risk is too much, use the
standard stainless steel cable in rear brake, and the CF or Aramid
fiber replacement in the front brake, until you have some confidence
in the idea.

Remember, you have but one life to give for advancing bicycle tech.

"Understanding The Subtle Differences Between Carbon Fiber And Aramid
Fiber"
https://pur-carbon.com/blogs/news/understanding-the-subtle-differences-between-carbon-fiber-and-aramid-fiber

Kevlar Ropes, Cables, and Fibers"
https://www.dupont.com/fabrics-fibers-and-nonwovens/ropes-cables.html

Jeff, try picturing threading a Kevlar inner cable through the outer. Now how would you expect to do that? As a real engineer I have some ideas that could work but why when stainless steel is more than sufficient. Jay is a lawyer and not a mechanic. We all know that he broke a cable probably because he overtightened it at the derailleur and broke the strands. Stainless is extremely good at weather resistance but very bad at pressures that overload the molecular bond of the material.

We use a coated Kevlar cord with ceramic magnet set to
thread wires through modern internal route frames. Passing
that through casing would not seem a barrier.

The failure mode of a steel or stainless steel gear wire is
fraying at the capstan and I doubt Kevlar/Aramid would give
any better life, likely worse.

The Trek uses a cable stop/port with entry holes the diameter of inner-wire liner, and in fact a liner with a flared end is placed in the hole. https://tinyurl.com/ecv585cj What this means is that you can't put the old and new cable ends together with a crimp-cable end and then pull the new cable through -- unless you remove the port and put the new cable through and crimp it to the old cable after the port. The good news is that its not hard to locate the cable if you just feed it into the frame through the port. There is a window at the bottom of the DT, and you just grab the cable with a hook. I'm re-doing both shift and a brake cable just because. And some new brake pads.

-- Jay Beattie.