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CABLE HOUSING: Brake for derailleur?



 
 
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  #1  
Old July 16th 03, 02:36 PM
default
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Default CABLE HOUSING: Brake for derailleur?

This might sound like a stupid question, but if you have a knowledgeable
answer I would appreciate it.

Is there any fundamental difference between brake and derailleur cable
housing?

What would be the problem with using "brake" housing for derailleur cable?

thanks............

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  #2  
Old July 16th 03, 03:22 PM
Jim Price
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Default CABLE HOUSING: Brake for derailleur?

default wrote:

This might sound like a stupid question, but if you have a knowledgeable
answer I would appreciate it.

Is there any fundamental difference between brake and derailleur cable
housing?


Yes. Brake cable housing usually has a spiral wound metal core, whereas
gear cabling is made using axial wires, held together by the outer
plastic. There are other variations, but these are the basic ones.

What would be the problem with using "brake" housing for derailleur cable?


It can work, but not as well. The gear cable housing changes length less
when bent (e.g. when you turn the handlebars). If you don't want to risk
changing gear when doing a very tight low speed turn, don't use brake
outers for gears. Oh, and don't use gear outers for brakes - it's not as
strong.

--
Jim Price

http://www.jimprice.dsl.pipex.com

Conscientious objection is hard work in an economic war.

  #3  
Old July 16th 03, 03:30 PM
default
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Default CABLE HOUSING: Brake for derailleur?

thnx jim -- thats exactly what i wanted to know.

Jim Price wrote:
default wrote:

This might sound like a stupid question, but if you have a
knowledgeable answer I would appreciate it.

Is there any fundamental difference between brake and derailleur cable
housing?



Yes. Brake cable housing usually has a spiral wound metal core, whereas
gear cabling is made using axial wires, held together by the outer
plastic. There are other variations, but these are the basic ones.

What would be the problem with using "brake" housing for derailleur
cable?



It can work, but not as well. The gear cable housing changes length less
when bent (e.g. when you turn the handlebars). If you don't want to risk
changing gear when doing a very tight low speed turn, don't use brake
outers for gears. Oh, and don't use gear outers for brakes - it's not as
strong.


  #5  
Old July 16th 03, 08:37 PM
CBike
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Default CABLE HOUSING: Brake for derailleur?

Actually the standard derailler housing sold is not adequate to handle the
compression required for brakes however there is newer housing available which
is designed for either use. Some types of JagWire housing is available which
uses longitudinal wires (used in current derailler housings) with an external
kevlar reinforced housing to give additional strength needed for brakes. This
product used on brakes can decrease the compression of the housing therefore
increase the amount of cable pull (very slightly). We've installed his on our
tandem and see some improvement in brake lever capasity.
Charlie Myer
Indiana
  #6  
Old July 16th 03, 08:42 PM
Paul Southworth
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Default CABLE HOUSING: Brake for derailleur?

In article , default wrote:
This might sound like a stupid question, but if you have a knowledgeable
answer I would appreciate it.

Is there any fundamental difference between brake and derailleur cable
housing?

What would be the problem with using "brake" housing for derailleur cable?


Rear derailleurs used with indexed shifting need a special kind of
housing which does not compress as much. It works a lot better
than brake cable housing. A small chunk of brake housing used from
the chainstay to the derailleur won't cause a problem if the cable
runs smoothly.

If you use friction style shifting then brake housing will work OK.

--Paul
  #7  
Old July 16th 03, 09:32 PM
Mike S.
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Default CABLE HOUSING: Brake for derailleur?


Rear derailleurs used with indexed shifting need a special kind of
housing which does not compress as much. It works a lot better
than brake cable housing. A small chunk of brake housing used from
the chainstay to the derailleur won't cause a problem if the cable
runs smoothly.

If you use friction style shifting then brake housing will work OK.

--Paul


I was doing this for years. Run SIS housing from the shifters to the frame,
then SLR housing for the loop for the rear derailleur. Did this recently
when I replaced cables and housing and just COULD NOT get the @#$ derailleur
to shift. Grumble, grumble. Scratch head. Hmmm, maybe...

Changed to SIS housing for the derailleur loop and everything worked like a
swiss watch.

Mike


  #8  
Old July 22nd 03, 10:25 AM
Shaun Rimmer
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Default Then what's the deal with Avid Flak Jackets? CABLE HOUSING: Brake for derailleur?


default wrote in message ...
Sorry to beat this horse........ but the reason I asked originally was
because I just bought a full set of Flak Jacket cables to redo my
bike..... and looking at the housing, I could not see a difference
between brake/shifter........

natch, there was no difference. These were new sealed cables, but they
are both the "lengthwise" housings.....

So I put it on the brakes. No problems yet.

So what is up with Avid. Did my package jsut get mislabeled at the

factory?

Does the housing have a braided (stainless steel braid or somesuch) cover,
between the outer plastic sheath, and the inner lengthwise strands? If so,
it's likely this will stop the inner strands from splitting and popping
through the outer sheath, and so the cables work for both brakes and gears.


Shaun aRe




  #9  
Old July 22nd 03, 04:57 PM
Joe Yannie
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Default Then what's the deal with Avid Flak Jackets? CABLE HOUSING: Brake for derailleur?

No, what Avidsays is that there is enough compression resistance in the
housing ( since it is kevlar based ) that it can be used for brakes and
shifters. I have used it for both with no problems.


"default" wrote in message ...
Sorry to beat this horse........ but the reason I asked originally was
because I just bought a full set of Flak Jacket cables to redo my
bike..... and looking at the housing, I could not see a difference
between brake/shifter........

natch, there was no difference. These were new sealed cables, but they
are both the "lengthwise" housings.....

So I put it on the brakes. No problems yet.

So what is up with Avid. Did my package jsut get mislabeled at the

factory?

Chris Zacho The Wheelman wrote:
If it's INDEXED derailer housing, yes. The steel in an indexed derailer
cable, instead of being wound into a tight coil (as in brake cables) is
instead arranged in lengthwise strands for more accurate shifting.

This makes the cable extremely resistant to compression (shortening)
while shifting, but very weak as far as rupturing goes.

_DO_NOT_USE_ indexed derailer cable housing for your brakes! This could
result in the cable breaking out of the housing and leaving you with no
brakes, at the worst possible time: When you're braking hard. I cannot
stress this enough. It is is a Very Bad Thing!

May you have the wind at your back.
And a really low gear for the hills!
Chris

Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner




 




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