Converting a Brake Cable To a Shifter Cable

Torch the end and shake off the solder until only a small nib is left.


Bret Cahill

On Mar 5, 5:39 am, "Bret Cahill" wrote:
Torch the end and shake off the solder until only a small nib is left.

Bret Cahill

Or go down to the bike shop and buy one. That brake inner wire isn't
going to fit well and smoothly in 4mm housing, BTW-

On 5 Mar, 12:39, "Bret Cahill" wrote:
Torch the end and shake off the solder until only a small nib is left.

Bret Cahill

Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and brake
cable is too stretchy for gears.

Simon

Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and brake
cable is too stretchy for gears.

Fortunately the metro bus managed to stop when I couldn't get into the
small chain ring in time.


Bret Cahill

Simon Ceze writes:

Torch the end and shake off the solder until only a small nib is
left.

Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and
brake cable is too stretchy for gears.

Oh! Explain how that can be so, considering they are both steel and
the brake cable has a larger cross section. This is a tale I haven't
heard yet although there is a difference between brake cable housing
and shift cable STI housing.

http://www.sheldonbrown.com/brandt/sis-cable.html

Jobst Brandt

On 06 Mar 2007 04:16:29 GMT, wrote:

Simon Ceze writes:

Torch the end and shake off the solder until only a small nib is
left.

Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and
brake cable is too stretchy for gears.

Oh! Explain how that can be so, considering they are both steel and
the brake cable has a larger cross section. This is a tale I haven't
heard yet although there is a difference between brake cable housing
and shift cable STI housing.

http://www.sheldonbrown.com/brandt/sis-cable.html

Jobst Brandt

Dear Jobst,

Why take such needless offense, snarl, sneer, and make new enemies?

Why not just explain that the cables are the same material, but that
the cable housings are different and refer him to your far more
pleasant article?

Cheers,

Carl Fogel

On Mar 5, 11:16 pm, wrote:
Simon Ceze writes:
Torch the end and shake off the solder until only a small nib is
left.
Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and
brake cable is too stretchy for gears.

Oh! Explain how that can be so, considering they are both steel and
the brake cable has a larger cross section. This is a tale I haven't
heard yet although there is a difference between brake cable housing
and shift cable STI housing.

http://www.sheldonbrown.com/brandt/sis-cable.html

Jobst Brandt

Mr. Brandt,

Can you clarify why if both SIS (shift) and SLR (brake) housings no
not compress, only SIS is recommended for the shifter? Your article
states that the SLR housing would change length when bent, but in the
case of indexed down-tube shifters (for which it was initially
developed) the only housing is at the back leading into the rear D.
But once the housing is installed, it does not turn or move so that
the length would then remain constant. (The same argument can be used
for the STI housing up front). I understood that the reason new
housing had to be develop was that the SLR housing would indeed
compress progressively with pressure, however minutely, so that
indexed shifting would not be reliable across the entire cassette.

Josh

On 5 Mar 2007 21:45:25 -0800, wrote:

On Mar 5, 11:16 pm, wrote:
Simon Ceze writes:
Torch the end and shake off the solder until only a small nib is
left.
Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and
brake cable is too stretchy for gears.

Oh! Explain how that can be so, considering they are both steel and
the brake cable has a larger cross section. This is a tale I haven't
heard yet although there is a difference between brake cable housing
and shift cable STI housing.

http://www.sheldonbrown.com/brandt/sis-cable.html

Jobst Brandt

Mr. Brandt,

Can you clarify why if both SIS (shift) and SLR (brake) housings no
not compress, only SIS is recommended for the shifter? Your article
states that the SLR housing would change length when bent, but in the
case of indexed down-tube shifters (for which it was initially
developed) the only housing is at the back leading into the rear D.
But once the housing is installed, it does not turn or move so that
the length would then remain constant. (The same argument can be used
for the STI housing up front). I understood that the reason new
housing had to be develop was that the SLR housing would indeed
compress progressively with pressure, however minutely, so that
indexed shifting would not be reliable across the entire cassette.

Josh

Dear Josh,

Brake cable housing compresses a bit, but it's very strong, so it
works fine for the heavy loads of braking and your squeezing fingers
adjust for the slight compression.

That slight compression would goof up the much lighter, but more
sensitive loads involved in shifting.

So an almost compressionless cable was developed to allow accurate
shifting.

Paradoxically, the compressionless shift cable is weaker than brake
cable--too weak for the heavy load of braking.

So if you use stiff but weak shift cable housing for brakes, you run a
strong risk of the cable housing failing just when you need it most.

Basically, brake cable housing is wound tightly and its coils squish
together under a heavy load, staying in place and compressing a
little, while the shift cable housing is barely wound at all and can
bulge and split under a heavy load.
_____________________
/////////////////
///////////////// tightly wound brake cable
///////////////// each of the many coils compresses a bit
---------------------
/
one brake coil /
a single helix /


______________________
_
_ ' - . _
_ ' - . _ barely wound shifter cable
' - . _ much less compression
-----------------------
_
one shifter coil ' - .
a single turn every 100 mm
18 separate wires

Cheers,

Carl Fogel

Carl Fogel writes:

Simon Ceze writes:

Torch the end and shake off the solder until only a small nib is
left.

Don't. Brake cable is slightly elastic - so that it's very
strong. Gear cable is more rigid - for precise shifting - but
that makes it more brittle. It is dangerous to use gear cable for
brakes, and brake cable is too stretchy for gears.

Oh! Explain how that can be so, considering they are both steel
and the brake cable has a larger cross section. This is a tale I
haven't heard yet although there is a difference between brake
cable housing and shift cable STI housing.

http://www.sheldonbrown.com/brandt/sis-cable.html

Why take such needless offense, snarl, sneer, and make new enemies?

Who should be offended when an anonymous poster under the guise of
"Simon says" gives much incorrect advice without flinching. Besides,
the FAQ item doesn't mention shift and brake cables, only housings. I
didn't notice calling the writer any rude names accusing him pf lying
or being stupid, as the peanut gallery does regularly and anonymously.
I notice they don't draw your attention to sensitivities.

Why not just explain that the cables are the same material, but that
the cable housings are different and refer him to your far more
pleasant article?

What wasn't explained and is unpleasant about the words I wrote. They
directly address the claims made with no extras. Maybe you could
write a demonstration response to Simon's posting and show what you
feel is appropriate.

Jobst Brandt

hcethgil? writes:

Torch the end and shake off the solder until only a small nib is
left.

Don't. Brake cable is slightly elastic - so that it's very strong.
Gear cable is more rigid - for precise shifting - but that makes it
more brittle. It is dangerous to use gear cable for brakes, and
brake cable is too stretchy for gears.

Oh! Explain how that can be so, considering they are both steel and
the brake cable has a larger cross section. This is a tale I haven't
heard yet although there is a difference between brake cable housing
and shift cable STI housing.

http://www.sheldonbrown.com/brandt/sis-cable.html

Can you clarify why if both SIS (shift) and SLR (brake) housings do
not compress, only SIS is recommended for the shifter? Your article
states that the SLR housing would change length when bent, but in
the case of indexed down-tube shifters (for which it was initially
developed) the only housing is at the back leading into the rear D.
But once the housing is installed, it does not turn or move so that
the length would then remain constant. (The same argument can be
used for the STI housing up front). I understood that the reason
new housing had to be develop was that the SLR housing would indeed
compress progressively with pressure, however minutely, so that
indexed shifting would not be reliable across the entire cassette.

I'm unclear on the question, but the difference between shift housing
and brake housing is that SIS shift housing has strands lengthwise in
a long helix the way cables have, and brake housing is made of a stack
of rings (slightly helical). The centerline of brake housing becomes
longer when the housing is bent, it standing close packed on the
inside of the coils in the bend and having light between coils on the
outside.

Cable, on the other hand remains constant length because all its
strands pass though the inside AND outside of a bend. That is why it
must be helically wound.

With indexed shifting and shift cable making every bend the handlebars
make could cause a mis-shift or a jump out of gear. What the rear
derailleur does is immaterial because its cable housing doesn't move
while riding.

Jobst Brandt