design question - cable placement

[Ed Stevens]

I just returned from dropping my bikes off for their annual tuneup at my LBS. While standing around
drooling over the new bikes on the floor I noticed that on some bikes the rear brake cable runs
along the lower quarter of the top tube, while on others it runs along the upper quarter. (Not to
mention those who run the cable inside the top tube.) I noticed that even within a given
manufacturer, this cable placement would vary from model to model. So my question is, what are the
design considerations on placement of the rear brake cable, that a manufacturer would choose to
place it on the upper quarter vs. the lower quarter vs. inside?

 

[Ken]

Ed Stevens <[email protected]> wrote in news:[email protected]:
> So my question is, what are the design considerations on placement of the rear brake cable, that a
> manufacturer would choose to place it on the upper quarter vs. the lower quarter vs. inside?

Traditionally, the brake cable is routed above the top tube. This allows you to mount a pump under
the top tube (road bikes) or shoulder the bike when crossing rivers or logs (mountain and cross
bikes). Modern dual suspension mountain bikes can't really be shouldered, though, so cable routing
doesn't matter much.

Ken

 

[Ed Stevens]

On Sat, 15 Feb 2003 19:11:27 +0000 (UTC), Ken <[email protected]> wrote:

>Ed Stevens <[email protected]> wrote in news:[email protected]:
>> So my question is, what are the design considerations on placement of the rear brake cable, that
>> a manufacturer would choose to place it on the upper quarter vs. the lower quarter vs. inside?
>
>Traditionally, the brake cable is routed above the top tube. This allows you to mount a pump under
>the top tube (road bikes) or shoulder the bike when crossing rivers or logs (mountain and cross
>bikes). Modern dual suspension mountain bikes can't really be shouldered, though, so cable routing
>doesn't matter much.
>
>Ken

Hmm. Well, these were all road bikes. I thought it particularly interesting that even in a row of
Litespeeds -- all roadies -- some models had the cabeling on top, some on bottom.

 

[S. Anderson]

To be honest, it simply doesn't matter most times. Some put it inside to make the bike look cleaner
and prevent the cable from marking up the top tube; some put it on top because it's easier than
inside and it looks the most symmetrical but does mark the top tube over time; some put it on either
the lower left or right because it's less likely to mark the tube or show those marks if it does,
but it looks lopsided. Honestly, it doesn't make much difference to the performance of the bike,
it's mostly show. Some bikes that have all cables over the top tube (ders and brake) do that using
the argument that mud and gunk are less likely to gunge up the cables and that may be a valid reason
technically. Otherwise, it's whatever happened to turn the designer's crank when he was drawing it
up. There is one caveat however: if the brake setup is funky for some reason (super small frame,
weird brake, seat post clamp cable hanger or something..) then the cable position may have to be a
certain way.

Cheers,

Scott..
--
Scott Anderson

"Ed Stevens" <[email protected]> wrote in message
news:[email protected]...
> On Sat, 15 Feb 2003 19:11:27 +0000 (UTC), Ken <[email protected]> wrote:
>
>
> Hmm. Well, these were all road bikes. I thought it particularly interesting that even in a row of
> Litespeeds -- all roadies -- some models had the cabeling on top, some on bottom.

 

[David L. Johnso]

On Sat, 15 Feb 2003 12:59:44 -0500, Ed Stevens wrote:

> would vary from model to model. So my question is, what are the design considerations on placement
> of the rear brake cable, that a manufacturer would choose to place it on the upper quarter vs. the
> lower quarter vs. inside?

My opinion would be on the top quarter. You should be able to shoulder the bike without the cable
irritating your shoulder. I don't like inside routing at all. Aside from the holes in the frame,
and the plastic tube that runs along inside so you can thread the cable through (what happens when
that comes loose?), you have to use the cable sheath all the way back, which adds friction on the
rear brake.

--

David L. Johnson

__o | Become MicroSoft-free forever. Ask me how. _`\(,_ | (_)/ (_) |

 

[Terry Rudd]

One advantage of the exterior routing is getting rid of the cable casing for up to 75% of the length
of the top tube. This helps reduce overall braking friction for the rear brake, gets rid of some
weight cheaply and looks cleaner.

Terry

S. Anderson wrote:
> To be honest, it simply doesn't matter most times. Some put it inside to make the bike look
> cleaner and prevent the cable from marking up the top tube; some put it on top because it's easier
> than inside and it looks the most symmetrical but does mark the top tube over time; some put it on
> either the lower left or right because it's less likely to mark the tube or show those marks if it
> does, but it looks lopsided. Honestly, it doesn't make much difference to the performance of the
> bike, it's mostly show. Some bikes that have all cables over the top tube (ders and brake) do that
> using the argument that mud and gunk are less likely to gunge up the cables and that may be a
> valid reason technically. Otherwise, it's whatever happened to turn the designer's crank when he
> was drawing it up. There is one caveat however: if the brake setup is funky for some reason (super
> small frame, weird brake, seat post clamp cable hanger or something..) then the cable position may
> have to be a certain way.
>
> Cheers,
>
> Scott..
> --
> Scott Anderson
>
>
> "Ed Stevens" <[email protected]> wrote in message
> news:[email protected]...
>
>>On Sat, 15 Feb 2003 19:11:27 +0000 (UTC), Ken <[email protected]> wrote:
>>
>>
>>Hmm. Well, these were all road bikes. I thought it particularly interesting that even in a row of
>>Litespeeds -- all roadies -- some models had the cabeling on top, some on bottom.
>

 

[Don Demair]

"Terry Rudd" <[email protected]> wrote in message news:[email protected]...
> One advantage of the exterior routing is getting rid of the cable casing for up to 75% of the
> length of the top tube. This helps reduce overall braking friction for the rear brake, gets rid of
> some weight cheaply and looks cleaner.
>

I agree with those points, however I had a problem with the cable rusting thanks to my profuse
perspiration which would drip onto the cable and wick into the housing and onto the cable stops. It
was making a bit of a mess over time and no amount of greasing the cable or cleaning the bike after
a ride seemed to help.

Finally, I modified the cable stops so I could run housing the whole length of the top tube. In my
case, it looks much cleaner and works better since there is no more rust build-up.

Ride on, fortunately, not every one sweats like me, Don

 

[Buck]

"Don DeMair" <[email protected]> wrote in message
news:[email protected]...
>
> "Terry Rudd" <[email protected]> wrote in message news:[email protected]...
> > One advantage of the exterior routing is getting rid of the cable casing for up to 75% of the
> > length of the top tube. This helps reduce overall braking friction for the rear brake, gets rid
> > of some weight cheaply and looks cleaner.
> >
>
> I agree with those points, however I had a problem with the cable rusting thanks to my profuse
> perspiration which would drip onto the cable and wick into the housing and onto the cable stops.
> It was making a bit of a mess over time and no amount of greasing the cable or cleaning the bike
> after a ride seemed to help.
>
> Finally, I modified the cable stops so I could run housing the whole
length
> of the top tube. In my case, it looks much cleaner and works better since there is no more rust
> build-up.
>
> Ride on, fortunately, not every one sweats like me,

Hey Don! Watch your stem and headsets carefully. I bought a used bike from a guy like you and
discovered later that the stem was corroded in place. I had to use a hacksaw to get it out. I then
discovered that the headset was also having problems. Then I noticed that the paint was bubbling in
areas where sweat could collect (cable stops, head tube). Ah, the corrosive nature of some people is
more than just their personality....

-Buck

 

[Terry Morse]

Don DeMair wrote:

> I agree with those points, however I had a problem with the cable rusting thanks to my profuse
> perspiration which would drip onto the cable and wick into the housing and onto the cable stops.

You can get stainless steel cables, as another option.
--
terry morse Palo Alto, CA http://www.terrrymorse.com/bike/

 

[Terry Rudd]

Terry (Morse),

I am pretty sure almost all cables are stainless today. What corrodes is the spiral steel in the
cable casing. Even with teflon sleeves, the corrosion can become a problem over time. I am not even
sure that a combination of a teflon coded stainless cable under such conditions will last for a
long time.

Terry Rudd

Terry Morse wrote:
> Don DeMair wrote:
>
>
>>I agree with those points, however I had a problem with the cable rusting thanks to my profuse
>>perspiration which would drip onto the cable and wick into the housing and onto the cable stops.
>
>
> You can get stainless steel cables, as another option.
> --
> terry morse Palo Alto, CA http://www.terrrymorse.com/bike/