29 tooth Campag Problem

Discuss light weight issues concerning road bikes & parts.
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chickenbourne
Posts: 35
Joined: Thu Dec 01, 2011 8:48 pm

by chickenbourne

I'm now running a 29 Chorus cassette (up from 25) on a Record rear mech. While tinkering I noticed that when in first gear the jockey wheel is close to the bottom of the 29th so that the chain makes a slight noise on an otherwise quiet set-up. I installed a new (and longer) chain when going up from the 25 in accordance with campag instructions, but have made no other adjustments. Am I missing something or have I made a school boy error of having my chain too long? Given its a Record chain with those stupid links I hope I'm just missing an adjustment somewhere....

by Weenie


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Stolichnaya
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Joined: Wed Oct 06, 2004 6:55 pm
Location: Vienna, AUT

by Stolichnaya

Most Campy derailleurs have a third set screw located at the cage pivits around the top pulley.
Adjusting that gives the upper pulley more space in relation to the cogs. (The Campagnolo site has good information about this set screw in case the description is not making sense.)
If you are running a short cage derailleur, getting it dialed in with a 29 may take a little more time but it will work.

chickenbourne
Posts: 35
Joined: Thu Dec 01, 2011 8:48 pm

by chickenbourne

I had spotted that screw and wondered what it was for. I'll check it out. Thanks for the tip :D

DaveS
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Joined: Fri Mar 24, 2006 1:26 pm

by DaveS

That screw should be turned CCW, to increase the clearance.

As long as the chain doesn't hang loose in the little ring and smallest cog, then it's not too long.

There are some Record RDs that won't provide enough clearance for a 29T cog, like the 2009 model 11 speed. Earlier model Record 10 short cage RDs are not intended for use with a 29T cog, either.

audiophilitis
Posts: 506
Joined: Sun Jul 29, 2012 12:49 am

by audiophilitis

That's interesting -- I just installed a SR 12-29 on a new wheelset, replaced cables, and made the necessary adjustments to make it shift properly. My other wheelset has a 12-25 cassette (same hub) -- wondering if I'd have to mess with the settings whenever I switch from 12-29 to 12-25. I'm hoping not but can someone chime in please to confirm? RD is a 2011 Campy SR (short cage). Thx.

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Calnago
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Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

Like DaveS said, the early 2009 11sp rear derailleurs need a modification to work with the 12/29 cassette. It's a simple replacement part (not overly expensive) that you can get. Then you're good. Newer derailleurs already have that modification done to coincide with the release of the 11sp 12/29. And there are no longer a short, med and long cage versions of the Super record derailleur. Good news is that you don't need it. Provided you have the correct chain length you should be able on run any cogset from 11/23 to 12/29, the only adjustment being a slight turning to the b-screw. I run a standard 53/39 crank and can interchange wheels using any combination of 11 spd cogs. The relevant cassettes I run are 11/23 (rarely), 12/25 (most of the time), 12/27 and 12/29.
The 10 spd versions had different cage lengths to accommodate the range if cassettes. The med cage was for the 13/29 cassette using a double chain ring up front. The long cage was to accommodate the 13/29 cassette and a triple crank up front.

chickenbourne
Posts: 35
Joined: Thu Dec 01, 2011 8:48 pm

by chickenbourne

DaveS wrote:That screw should be turned CCW, to increase the clearance.

As long as the chain doesn't hang loose in the little ring and smallest cog, then it's not too long.

There are some Record RDs that won't provide enough clearance for a 29T cog, like the 2009 model 11 speed. Earlier model Record 10 short cage RDs are not intended for use with a 29T cog, either.


There's no hanging loose on my chain! Record 2011 (red 11 on the decal) so I guess I should be okay with some CCW turns. Thank you

fdegrove
Tubbie Guru
Posts: 5851
Joined: Tue May 03, 2005 2:20 am
Location: Belgium

by fdegrove

Hi,

The med cage was for the 13/29 cassette using a double chain ring up front.


13/26 max for the short cage 13/29 for the medium one. This made the medium cage the best buy (on paper) but I doubt it actually sold all that well.

Ciao, ;)
Being a snob is an expensive hobby.

audiophilitis
Posts: 506
Joined: Sun Jul 29, 2012 12:49 am

by audiophilitis

Calnago wrote:Like DaveS said, the early 2009 11sp rear derailleurs need a modification to work with the 12/29 cassette. It's a simple replacement part (not overly expensive) that you can get. Then you're good. Newer derailleurs already have that modification done to coincide with the release of the 11sp 12/29. And there are no longer a short, med and long cage versions of the Super record derailleur. Good news is that you don't need it. Provided you have the correct chain length you should be able on run any cogset from 11/23 to 12/29, the only adjustment being a slight turning to the b-screw. I run a standard 53/39 crank and can interchange wheels using any combination of 11 spd cogs. The relevant cassettes I run are 11/23 (rarely), 12/25 (most of the time), 12/27 and 12/29.
The 10 spd versions had different cage lengths to accommodate the range if cassettes. The med cage was for the 13/29 cassette using a double chain ring up front. The long cage was to accommodate the 13/29 cassette and a triple crank up front.


Based on your experience, did switching from 12/25 to 12/29 or vice versa require adjustment of the derailleur cage screw?

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Calnago
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Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

If it's adjusted for the 29 then you would be fine switching to the 25 with no further adjustment. Nonetheless, I do tweak it a bit just to get it "perfect" but can't say I really notice a difference. However, if it is adjusted for the 25 and you're going to the 29 then I would for sure check it out just to make sure the chain/pulley aren't jamming into the teeth.

audiophilitis
Posts: 506
Joined: Sun Jul 29, 2012 12:49 am

by audiophilitis

Calnago wrote:If it's adjusted for the 29 then you would be fine switching to the 25 with no further adjustment. Nonetheless, I do tweak it a bit just to get it "perfect" but can't say I really notice a difference. However, if it is adjusted for the 25 and you're going to the 29 then I would for sure check it out just to make sure the chain/pulley aren't jamming into the teeth.



Makes perfect sense -- thanks!

by Weenie


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