I'm having a small problem with the rear derailleur on my bike.

I recently stripped the bike down and cleaned everything to rebuild it (usual six month maintanance) and noticed when installing the rear derailleur that before the attachment bolt comes up to suitable torque the derailleur binds up and becomes very tight, i.e. it will not move freely forwards and backwards.

When I installed it I used a T25 torx in the inboard side of the bolt because I did not have a suitably long enough torx drive to bolt in the normal way.

On the end of the bolt, ie where the thread first attaches to the derailleur hanger the end of the bolt has a T25 torx female end. I placed the T25 bit into the end and then reversed the bolt into the derailleur hanger to attach it. When tightening up I noticed that the forward and backwards movement that normally is quite free too move became increasingly stiffer as I torqued the bolt up.

I have since obtained a long enough T20 torx driver to attach in the normal way but now when I put any decent torque (2.3Nm) into the bolt the derailleur binds up again. I certainly can't put 15Nm into it as suggested by Campagnolo.

Ahhhhhhh !!! It's driving me mad !!!!

Does the Campy attachment bolt have a bolt within a bolt, i.e. have I by using the reverse method to attach the derailleur somehow tightened one bolt onto another thus increasing the friction in the attachment which is now causing the binding issue ???

I will run the bike as it is for a short ride but feel it is not great and worry that the attachment bolt may macome loose due to vibration.

Help me please !!!!!

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Enigma Echo

Not sure how experienced you are from your description. If this is new for you - have you made sure you are allowing the tab on the RD to clear the stop on the hanger?

If you are not doing this then you will get exactly this situation. Don't ride with it BTW.

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dangerous curves ahead

http://www.campagnolo.com/repository/do ... -03-12.pdf

The tech drawing does show a bolt within a bolt as you guessed.
Maybe the spring end has come out of its retaining hole and binds when you tighten the bolt.

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r o y g b i v

I'd like to see how that "bolt within the bolt" is fastened together. If it's a threaded connection, you would think there would be a risk of it coming apart on removal. Press fit?

Interesting that no P/N shown either.

Below Chorus it's a conventional one-piece bolt.

Maybe the tech manual has something?

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dangerous curves ahead

Yes I have chekced the tab is in the correct place, it's not the tab that is binding up but there is friction somewhere stopping it from moving freely.



Many thanks for the tech download. As you say it does show a bolt within a bolt which I thought. From the Chorus up to SR it shows this two-piece bolt within a bolt.

I think it will be best for me to put a T25 torx on the inward bolt and try to undo it whilst holding the outward bolt from moving, that should untighten it I think? Then I will untighten and remove the derailleur and reinstall without touching the inward bolt ?



Me too



Sorry, can you explain P/N?



I would like to see the workshop manual if anybody has one.

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Enigma Echo

Just found this http://forums.roadbikereview.com/compon ... 64141.html" onclick="window.open(this.href);return false; which also asks the same questions but no conclusion.

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Enigma Echo

there was an answer of sorts in the last post



It looks to be firmly fixed together, so I can't see it as the cause of your problem unless it's come apart by accident!

P/N just means Part Number.

The tech manual can be downloaded from their site - but there was no help there - I checked.

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dangerous curves ahead

I know what you mean but I think that is just a standard answer from the manufacturer ... "Send it to an approved Campag dealer for national Campag importer to fix" ...

I just spoke to my LBS who has said it is simplay a case of undoing what I did.

In my case this would be holding the outwards bolt (the correct one) static and undoing the inboard one to loosen the torque between them which shoudl be enough to back off the tightness in the derailleur and allow freere movement when I torque it back up using only the outward bolt.

I'll give it a try later and see how I get on.

Cheers,

Si

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Enigma Echo

Ok, so that didn't work

I didn't want to wrench to hard on it so it looks like a trip to the LBS is in order

I feel bad really cos I never go there unless I've made a silly mistake

Ah well, everyday is a school day, shame there is no information online / manufacturers site to give details on this. A simple "don't do this" in the installation manual would help, like they do when they warn of reverse (left hand) threads etc ...

Hopefully it is just that and it's not totally buggered.

I can get about 5Nm on the bolt before it starts to bind up / get too stiff to move easily.

The funny thing is the bike still runs fine and shifts ok, the only thing tha worries me is if it does loosen (most likely on a bumpy descent) then chances are I am coming off or at the very least gonna have a big repair bill.

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Enigma Echo

LBS has suggested it is a warranty issue, so it's back to Campag for fixing / replacement.

In the meatime a new rear derailleur has been bought (so im not off the road for too long), quite happy to have a spare anyway so it's all gravy !!!

I guess some things just can't be fixed !!!

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Enigma Echo