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

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!!

On Mon, 18 Jul 2005 14:56:25 +0200, RNK
wrote:

Matt wrote:
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.



Another advantage of bottom routing is that
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.


Robin


Life is Good!
Jeff

NoNeedForAName writes:

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