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An unintuitive fix for a chattery Campy rear derailleur.

Posted: Sun Dec 29, 2013 4:30 am
by Bridgeman
Just recently I discovered that my right shift lever clamp had loosened, thereby letting the lever assembly work its way downward on the bar. When I peeled back the bar tape I found that the shift cable housing had separated away from the lever housing.

After repositioning the lever housing upward to its rightful place I inserted the cable housing fully into the lever housing, re-taped the cables and re-wrapped the bar tape.

The result was incredible. The shifting just pops now, like when it was brand new! It's clear that if the shift cable end is allowed to have a gap, even as little as a millimeter or less the rear derailleur is going to exhibit hysteresis.

Since in my case the lever housing had shifted downward by an imperceptible amount (at least in the early stages) it had enable a gap to form between the cable housing and the lever housing. This was happening over the past few years, and all this time I was thinking the rear derailleur was wearing out (6+ years old), or as was pointed out recently my shifter ratchet may have begun to wear out in the lever mechanism.

The shifting is so good that I'm rethinking the need to go electric. Thought I'd pass this along.

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Sun Dec 29, 2013 7:20 am
by OrPe
Good piece of information.
thanks :) :thumbup:

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Sun Dec 29, 2013 7:20 am
by Weenie

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Sun Dec 29, 2013 10:24 am
by DMF
How could this possibly happen over the course of a few years... Unless... Unless, you don't regularly change your cable and housing? Repent my son, oh repent your misdeeds! ;)

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Sun Dec 29, 2013 7:08 pm
by em3
...so, what you are saying is that if your Campy ergolever is properly installed and fixed to your handlebars then you should expect optimum performance? :roll:
EM3

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 4:26 am
by Bridgeman
* When I change shifter cables (approx. once a year) I just thread them through the existing housings. I never swap out housings unless I assemble a new group.

* Years back when this group was assembled I splurged once and had it done by a pro. He was the head mechanic for a top Euro Pro Team. Stuff can come loose.

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 9:27 am
by mattr
Weird that. I redo cables (inner and outer) every time my bar tape needs replacing. Probably 5-6000 miles. And I've never come across loose shifters in that time frame. So how long has that tape been on there?
(And I have come across the same issue on a bike I serviced years ago)

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 4:12 pm
by Butcher
My first thoughts were the same as em3.

Stuff comes loose because it was not installed/torqued correctly. Pro or no Pro. Thinking a Pro does not make mistakes is a wrong way to go through life. We are all human therefore mistakes/accidents happen.

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 9:26 pm
by stella-azzurra
How do you guys need a cable change after 5000 miles? :noidea:
I've yet to make a cable change and the bike has way more than 15 thousand miles.

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 9:47 pm
by mattr
Cos my training bike gets ridden in all weather.
My race bike gets hammered. (Well, it used to)
My cross bike needs it.

And once the bar tape is off, cos it's bald/ripped/manky, for the sake of 10 quid, you may as well. Saves taking of nearly new tape to replace an outer.

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 9:52 pm
by Bridgeman
What Stella-Azzurra said. I rest my case.

As for stuff coming loose; do I wish it hadn't happened? Yes. C'est la vie

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Mon Dec 30, 2013 10:34 pm
by madcow
You'll find that even with everything tight you'll still get a similar affect over time. The parallel wires inside the housing will slowly work their way out of the end of the casing and allow the system to compress a little more during shifting. It's a good idea when using standard derailleur housing to replace it at least once a year. This isn't a problem with most stock brake housing since it is spiral wound.

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Tue Dec 31, 2013 12:58 am
by tommasini
I've seen the same on several occasions with the outers - the parallel housing wires working their way out of alignment at the ends. When I change bar tape I also do a check for this at the same time (all cable ends - not just the ends at the levers) - my fix is to use a small rotary grinder to square them up again - all goes well for another year or so. End result is I only replace housings (and inners) about every 4 years. One reason I came to that time frame conclusion is many folks seem to profess it's needed annually (about 6K miles for me), yet once I do replace both inner and outer every 4 years I don't see any change in performance............hmmmm, maybe I need to stretch the replacement interval out even longer??? 8) 8)

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Tue Dec 31, 2013 12:58 am
by Weenie

Re: An unintuitive fix for a chattery Campy rear derailleur.

Posted: Tue Dec 31, 2013 3:18 am
by Bridgeman
Yes, squaring up the ends really helps. In the early days of the ergo lever an end cap for the shift cable housing was to be included. This kept the wires together, but now they have done away with the end cap.

I think a good solution would be to cut the cable housing to proper length, square the wire ends and then affix end caps with a very robust epoxy. I would also look into somehow locking the end of the cable into the lever housing counterbore. Could be done with a simple spring clip.

As a side note, I've always thought the indexing function should have been integrated into the derailleur, but that"s another subject.