Broken rear derailleur

Discuss light weight issues concerning road bikes & parts.
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owl
Posts: 429
Joined: Tue Mar 15, 2005 11:59 pm
Location: Cambridge

by owl

Hi there

My campag rear derailleur is playing up. When I move the chain into the inner chain ring, the rear derailleur does not seem to be taking up the slack. As a result the chain is slapping the chainstay. At first I thought my chain length was too long, I trimmed the chain by 2 links which has made no difference. Hence I think it is the rear derailleur. Has anyone come across this before?

Thanks

owl
Owl

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theremery
Posts: 2673
Joined: Sun Jun 12, 2005 10:56 am
Location: New Zealand

by theremery

try moving the jockey wheel cage. Does it have spring tension remaining?
Updated: Racing again! Thought this was unlikely! Eventually, I may even have a decent race!
Edit: 2015: darn near won the best South Island series (got second in age
-group)..woo hoo Racy Theremery is back!!

owl
Posts: 429
Joined: Tue Mar 15, 2005 11:59 pm
Location: Cambridge

by owl

Thanks - yes there is plenty of spring in it comes back with real force - could it be chain length still. In 53/25 it looks plenty tight

Thanks

owl
Owl

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stella-azzurra
Posts: 5072
Joined: Mon Jan 23, 2006 6:35 am
Location: New York

by stella-azzurra

Whats' 53/25? :noidea: Hopefully not your front chain rings.
I never took drugs to improve my performance at any time. I will be willing to stick my finger into a polygraph test if anyone with big media pull wants to take issue. If you buy a signed poster now it will not be tarnished later. --Graeme Obree

timzcat
Posts: 315
Joined: Thu Sep 30, 2010 5:50 am

by timzcat

53/25 I am sure is big big.

rambotan
Posts: 34
Joined: Thu Aug 25, 2011 6:47 am

by rambotan

stella-azzurra wrote:Whats' 53/25? :noidea: Hopefully not your front chain rings.


53T Front and 25T Rear

alexalecu
Posts: 44
Joined: Tue Sep 28, 2010 5:13 pm
Location: BC, Canada

by alexalecu

Adjust the b-screw.

owl
Posts: 429
Joined: Tue Mar 15, 2005 11:59 pm
Location: Cambridge

by owl

thanks for that I will loosen the b screw, to pull the cage further away
Owl

BobSantini
Posts: 292
Joined: Sun Jul 10, 2011 9:03 am

by BobSantini

If your freehub is binding for some reason (freewheel bearing seizing or broken pawl in the gubbins or cogs touching spokes or ....) then the chain slack will occur at the top of the chain as you describe whenever you stop pedaling.
r o y g b i v

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bikerjulio
Posts: 1901
Joined: Fri Dec 11, 2009 10:38 pm
Location: Welland, Ontario

by bikerjulio

chain slap is obviously more likely when in the small ring since the chain is much closer.

here's a pic of a big-big combo with the RD extended as far as you'd want to go

Image

and in the small-small

Image
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

http://www.youtube.com/watch?v=GekiIMh4ZkM

owl
Posts: 429
Joined: Tue Mar 15, 2005 11:59 pm
Location: Cambridge

by owl

Thanks for all the advice. The answer - bobsantini you were the correct. Over the winter I put a miche primato cassette on for my turbo, put about 600 miles on it on the turbo and took off a recon cassette which I put on for 2 short rides at the end of last season. The miche primato cassette is slightly too wide causing it to seize the freehub when freewheeling when the cranks are at 11/4 o'clock if that makes sense (what a crock of shi@!).

I swapped cassettes and chain - problem solved. Wont sell my recon cassette now :wink:
Owl

Geoff
Posts: 5098
Joined: Sat Dec 13, 2003 2:25 am
Location: Canada

by Geoff

That B-screw needs to be adjusted...

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