CABLE HOUSING: Brake for derailleur?

[default]

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............

[Jim Price]

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.

[default]

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.
>

[Alex Rodriguez]

In article >, says...

>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, there is a difference. Once is spiral wound, and the other is edge wound.

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

Using brake casing for a derailleur cable is probably not going to be a big
deal. Your shifting may suffer a bit, but it should be ok. Never use
derailleur casing for your brakes. The casing cannot take compression and
could fail when you need it most.
-----------------
Alex __O
_-\<,_
(_)/ (_)

[CBike]

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

[Paul Southworth]

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

[Mike S.]

> 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

[Shaun Rimmer]

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

[Joe Yannie]

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
> >
>