fatherjac

I have just installed a new Campagnolo Chorus 12 speed Groupset to my Colnago C60 and I cannot get the rear mech adjusted to eliminate chain skipping/noise on the cassette. I have the 48/32 chainset and 11-34 cassette. I have installed many Campagnolo group sets over many years and never had a problem I couldn't resolve until now. I have used all the normal set up procedures from aligning the first cog, setting the end stops and the B screw etc. I cannot find any adjustment position where the chain runs quietly on all cogs. I can get it to run well on the top 4 and the bottom 4 but the middle 4 of the cassette run noisy. Adjusting the middle cogs leads to misalignment on the top and bottom cogs. I have tried everything I can think of to no avail including

1. checking the hanger alignment and resetting
   
2. checking cable for stickyness
   
3. checking the rear mech hinges for stiffness
   
4. refitting the cassette and trying it on a different wheel
   

I have spent many hours on this and am now well and truly stuck.

billridesbikes

I know this might sound weird and kind of a long shot but have you taken a calibers and measured the distance between all the cogs? I once got a Campy cassette (10sp) that had a similar problem but it appears that an incorrect spacer was used between one of the middle cogs causing the chain to skip and grind in that gear.

fatherjac

Thanks Billridesbikes. Apparently the 12 speed spacers are the same dimensions as the 11 speed. This, I believe, was to ensure compatibility between11 speed and 12 speed setups. So I used an 11 speed spacer to check the 12 speed cassette. It appears to be very slightly thicker which was a surprise. Just to check the compatibility, I then fitted the spare 11 speed wheel to the 12 speed bike. Everything worked perfectly with very smooth and slick shifting!!. WOW! this was a huge surprise and I am confounded!

Tomorrow I will take the 12 speed cassette apart and do accurate measurements before contacting the supplier for a possible replacement cassette.

Thanks so much for your idea Billridesbikes. I shall of course report back here with how things transpire.

SJX426 

@fatherjac - Is the chain on backwards? Some are not reversible.

fatherjac

OK I clearly have been deluding myself on this. I have checked the specifications and the dimensions of the spacers and they are as specified (2mm). The 11 speed are 2.2mm. Back to square one. .......More later.

RocThrower

Hey fatherjac

I just peeked at the Campy 12 Speed Cassette document. They seem to point out that the correct order of spacers is important. I'm sure you have this correct, but just in case.

Crankycrank

Something is wrong there. The 11 speed cassette should not work with 12 speed shifters. Is it possible the shift cable is clamped on the wrong side of the clamp bolt? You mentioned measuring the cassette spacers but did you also measure the thickness of the cogs? Also found this from the Campy FAQ's page.

Q. "I'VE GOT A 12-SPEED SUPER RECORD OR RECORD REAR DERAILLEUR. CAN I USE AN 11-34 SPROCKET BOX?

A. Yes, but only if the internal rocker indicates 29-34".

fatherjac

Thanks Rockthrower. The cassette is assembled correctly.

fatherjac

Thanks Crankycrank, As I said I was deluding myself a bit when I tried the 11speed block. I have spent a lot of time trying to resolve this problem and I was was being "excessively optimistic". It did work quite well on the 11 speed block though.

Protalus

I have had exactly the same problem with my Record 12 speed group set for 2 year. Can never get set up so that it is quiet across whole range. Either middle gears on cassette are ok, or outer ones, but never all. To and fro to l9cal campy specialists many times and they have also been in touch with Campy. Still no resolution. It’s ruining my joy of the bike and I am fed up.

DaveSSS 

Unless you have the cable incorrectly fastened to the RD, shifts to the larger sprockets should not be a problem, if the cable tension is set correctly. It's usually shifts to smaller sprockets where cable friction causes problems, particularly on frames with internal cable routing.

I used Campy for 25 years and the only groups I had a problem with were the chorus 12 on internally routed frames.

I switched to sram axs 12 last August. No regrets.

grandefuturo

Same issue here.
​​​​​​Relpaced Chorus 11s with brand new purchased 12s.

This looks like an indexing issue.
Large chainring:
Towards the smaller cogs, the shifter cable needs to be tightend. Towards the larger cogs, more released. No setting fits for all.

Small chainring :
When on the 2nd large cog, the chain scratches at the largest cog. When on the 2nd smallest cog, the chain scratches at the smallest.

It already starts earlier:
when on 3rd largest, scratching on 2nd largest.
releasing the cable helps.

when on 3rd smallest, scratching on 2nd smallest, tightening the cable helps.

When on the largest cog, it is ok, because there is no further cog above to scratch.

When on the smallest, it is ok, because there is no further cog below..

jiuralde

I have exactly the same problem.
I have changed cables, hanger aligned, greased etc. but nothing.
Have you finally been able to solve the problem?

jiuralde

I have exactly the same problem.
I have changed cables, hanger aligned, greased etc. but nothing.
Have you finally been able to solve the problem?

grandefuturo

​​​​​​I pulled the hanger a little outwards. Approx 1 cm more distance to the rim (bottom) than top. Now it works better. Almost perfect, but only almost.

fatherjac

I did eventually solve this problem. by taking the bike to a Campagnolo approved dealer. They were not forthcoming on how they resolved the issue, even when pressed. However the system has worked beautifully for the last few years now, although I have not had the courage to do more than very minor adjustments to it. I have been using Campagnolo all my cycling life(over40 years) and have aways installed and maintained parts myself so I was very frustrated by this problem.


I would of course be very interested to hear how you resolve the issue.

RGMN

This post from gfk_velo goes over a number of the causes of shifting issues: https://www.bikeforums.net/21977917-post10.html

FWIW check that your cassette lockring is properly torqued down. I've fixed a number of Campag systems that had shifting issues simply by torquing the cassette lock-ring with a torque wrench to the torque specified on the lock-ring.

grandefuturo

I almost fixed it by pulling the hanger a bit outside. As mentioned in the instruction manual, the hanger should point a bit outside. Thought this is the case with straight aligned eye....but it isn't. Need to pull the eye a bit outside, with the adjustment tool now approx. 1cm more distance at bottom side of rim than upper side. IMHO, this is a construction issue. Too many complains here with exactly the same issue, in particular with the 11-34 sprocket. It works now almost perfect. Almost.

jiuralde

Indeed the tightening torque is important. It makes an "accordion" effect that makes the cassette narrow or widen depending on the tightening torque.

Kontact 

What instruction manual?

grandefuturo

As a newbie, I am not allowed to share external links here.
​​​​​​
just search for
INSTALLATION OF 12-SPEED MECHANICAL GROUPSETS
YouTube · Campagnolo Official

​​​​​​Watch at about 6:15

or check instruction manuals from Campa website download section.

this outward bound of the hanger.

Kontact 

They aren't saying to bend your hanger out. They are saying the derailleur itself has a natural tilt. You misunderstood.

Please don't try to set up your bike with a non-straight hanger, and please don't tell people that's the way to do it.

grandefuturo

Not misunderstood. I expected this natural tilt of the derailleur, but there is none. Brand new unused 12s Chorus 11-34. The non-straight hanger solved it for me. Campa officials should tell how to fix this issue correctly. Thanks.

Kontact 

What did Campa Tech officials say when you spoke to them? Because it isn't going to be to bend your frame out of spec.

Derailleurs moving too far per click is usually caused by attaching the cable to the fixing bolt incorrectly. Look at 5:10 in the video:

Otherwise, take a look at your BB cable guide, and see if it moves at all when you shift the front derailleur. On some bikes the cable tension change on the FD cable will cause the cable guide or cable stop to pivot around it's mounting bolt, causing the RD cable to change tension.