Why aren't cables routed on top of top tube?

Gooserider said:

My road bike has cables routed under the top tube, and that causes damage to
my paint job when I put the bike in my storage rack. My MTB has cables on
the top of the tube---no damage. Is there a reason for the different setup?

I am no expert, but one of the main differences I noticed between road
and cyclocross bikes is that many of the cross bikes run all three of
the cables on the top of the top tube. I would assume that this is
so that when the rider dismounts and puts the bike over his shoulder,
the cables don't get disturbed.
I would think that it may be the same reason for MTBs.

"Gooserider" <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

My road bike has cables routed under the top tube, and that causes damage
to my paint job when I put the bike in my storage rack. My MTB has cables
on the top of the tube---no damage. Is there a reason for the different
setup?

Seems to me that most road bikes have the cables above the top tube.
Some have internally routed cables.

"Ken" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Gooserider" <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

My road bike has cables routed under the top tube, and that causes damage
to my paint job when I put the bike in my storage rack. My MTB has cables
on the top of the tube---no damage. Is there a reason for the different
setup?

Seems to me that most road bikes have the cables above the top tube.
Some have internally routed cables.

My experience is different. I have a Supergo MTB frame with cables on top of
the top tube. I have a Schwinn Peloton road bike---rear brake cable UNDER
top tube. My Gunnar Sport road bike has the rear brake cable on the side of
the top tube, and my Ibex flat bar roadie has it under the top tube. The
Schwinn developed big gouges under the top tube before I noticed it.

spin156 said:

Gooserider said:

My road bike has cables routed under the top tube, and that causes damage to
my paint job when I put the bike in my storage rack. My MTB has cables on
the top of the tube---no damage. Is there a reason for the different setup?

I am no expert, but one of the main differences I noticed between road
and cyclocross bikes is that many of the cross bikes run all three of
the cables on the top of the top tube. I would assume that this is
so that when the rider dismounts and puts the bike over his shoulder,
the cables don't get disturbed.
I would think that it may be the same reason for MTBs.

I was going to post the same unscientific knowledge, but then I
remembered all the old road bikes with the above-style cabling. Dunno
why it changed to underneath later on, but I do know that MTB's are on
the top for the shoulder thing.

Eric Hill <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

spin156 said:

Gooserider said:

My road bike has cables routed under the top tube, and that causes
damage to my paint job when I put the bike in my storage rack. My MTB
has cables on the top of the tube---no damage. Is there a reason for
the different setup?

I am no expert, but one of the main differences I noticed between
road and cyclocross bikes is that many of the cross bikes run all
three of the cables on the top of the top tube. I would assume
that this is so that when the rider dismounts and puts the bike over
his shoulder, the cables don't get disturbed.
I would think that it may be the same reason for MTBs.

I was going to post the same unscientific knowledge, but then I
remembered all the old road bikes with the above-style cabling. Dunno
why it changed to underneath later on, but I do know that MTB's are on
the top for the shoulder thing.

My GT (2003 Avalance 1.0) has the rear brake & derailleur cables under
the top tube, but due to the sloping TT and long seatpost, it's always
been more comfortable to carry it with the nose of the saddle on my
shoulder, and easier to pick up and put down. It's a PITA, though, to
work on the rear brakes when it's on my hanging rack, because of the
cable pinched on the hooks. Move the bike forward an inch and it rests
on the housing stops and I'm fine.

I'd imagine the frame designer of my bike (and yours) thought that
below-the-tube was a cleaner look. My GT also has a bottom-pull FD,
presumably for the same reason.

-Hank

Quoted message said:

I am no expert, but one of the main differences I noticed between road
and cyclocross bikes is that many of the cross bikes run all three of
the cables on the top of the top tube. I would assume that this is
so that when the rider dismounts and puts the bike over his shoulder,
the cables don't get disturbed.
I would think that it may be the same reason for MTBs.

MTBs run cables on top to keep them out of the mud and crud - I would
assume the same for cross bikes.

Gooserider said:

My road bike has cables routed under the top tube, and that causes damage to
my paint job when I put the bike in my storage rack. My MTB has cables on
the top of the tube---no damage. Is there a reason for the different setup?

MTB & cross bikes have them on top for carrying (else they dig into
shoulder, road bikes under (less noticable, looks neater). Besides
appearance, another downside to having them on top is catching them with
a shoe when you swing a leg over.

My experience is that most road bikes have the cables below the top tube. I
think this is because routing below eliminates the whacking of the cable on
the toptube when you hit bumps. Another advantage of bottom routing is that
less sweat gets into the braze ons with less rust as a result. Older bikes
(pre-brazeons) I think generally had the cable stops on top. When they
rotted away you could just pop them off & replace them.

MOO,
Matt

"Ken" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Gooserider" <[email hidden]> wrote in
news:[email hidden]:

Quoted message said:

My road bike has cables routed under the top tube, and that causes damage
to my paint job when I put the bike in my storage rack. My MTB has cables
on the top of the tube---no damage. Is there a reason for the different
setup?

Seems to me that most road bikes have the cables above the top tube.
Some have internally routed cables.

Matt said:

My experience is that most road bikes have the cables below the top tube. I
think this is because routing below eliminates the whacking of the cable on
the toptube when you hit bumps.

When you hit a bump and the cable whacks the top tube it sounds to me
like the cables have too much slack in them.

Another advantage of bottom routing is that

Quoted message said:

less sweat gets into the braze ons with less rust as a result. Older bikes
(pre-brazeons)

Yeah, but sweat dripping on the top tube will eventually drip to the
bottom of the top tube and drip on the cable anyway, if it's mounted in
the middle of the tube...

Robin

I can't tell you why . but neither did any body else. But I can tell you how
to keep the damage from being to much .They sell cable covers kind of .Avid
flack jackets and A company called Jagwire that make different brake
parts.You can buy a kit from Jagwire to put the cables in a little sleeve .
It also helps keep the cables clean .I have the Jagwire set up on 2 of my
bikes.You use your cables
and not that hard to install.
Good luck .

--
J/O TrailBlazer At Large!!

RNK said:

Matt said:

My experience is that most road bikes have the cables below the top tube. I
think this is because routing below eliminates the whacking of the cable on
the toptube when you hit bumps.

When you hit a bump and the cable whacks the top tube it sounds to me
like the cables have too much slack in them.

That is not necessarily true. Cable tension is determinned by need. If
there is too much slack, the brake lever will hit the bar, before the
brake is able to effectively stop the bike.

When I upgraded the STI shifter/brake levers on my LeMond, I forgot to
replace the two cable donuts. The cable was hitting the tube tube. I
think it has to do with the length of the exposed cable. I put three
donuts on and that took care of it.

Quoted message said:

Another advantage of bottom routing is that

Quoted message said:

less sweat gets into the braze ons with less rust as a result. Older bikes
(pre-brazeons)

Yeah, but sweat dripping on the top tube will eventually drip to the
bottom of the top tube and drip on the cable anyway, if it's mounted in
the middle of the tube...

Maybe, but to a lesser extent. Actually they're usually offset to the
left.

Quoted message said:

Robin

Life is Good!
Jeff

NoNeedForAName said:

MTBs run cables on top to keep them out of the mud and crud - I would
assume the same for cross bikes.

Agree; Raleigh routed cabling under the top tube, but as you sight
down the tube it's roughly at 4:30 or 5 o'clock, and this never seemed
to interfere with me carrying the bike on my shoulder.

IMHO, MTB bikes route on the top tube to (a) run the cable in the open
(less friction), and (b) use the tube as a mud/splash guard.

Older road bikes ran cables on the top tube because it was thought
that brazing anything to the tubes would weaken the tubes. However,
sweat would gather on the clamps and between the brake housing and the
tube and ruin the paint / rust the tubes pretty quickly (some people
have molecular acid for sweat), which was ironic because the goal was
to preserve tube strength; the result was weakened rusty top tubes.

- Don Gillies
San Diego, CA

On 18 Jul 2005 11:38:14 -0700, [email hidden] (Donald Gillies)

Quoted message said:

Agree; Raleigh routed cabling under the top tube, but as you sight
down the tube it's roughly at 4:30 or 5 o'clock, and this never seemed
to interfere with me carrying the bike on my shoulder.

The only problem I have with that routing is that it is easy to push
the cable against the tube and remove the paint. Most every bike with
the cable routed this way (many makes) had some paint chips. The cure
I found on a bike (can't remember which make) was to put a very small
diameter clear plastic tube on the cable between the braze on guides.
Nowadays donuts do most of that job.

(Nope, the cables didn't rust... in fact, it seemed to protect them)