campagnolo shifting problem

Discuss light weight issues concerning road bikes & parts.
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PINARELLOF8
Posts: 4
Joined: Wed Jan 01, 2020 4:52 am

by PINARELLOF8

Hello,
I am trying to get some inputs here :

I am using EPS V2 11s super record groupset (short cage) on an Pina F8 with chainstay = 406mm. Currently trying to make my gears lighter for my upcoming mountain trip. Here is what happened:
1. I'd a compact crack and changed my cassette from 12-25 to 12-29T It is possible to shift in all combinations except big-big. The eps refused to move up to the largest cog
2. I then suspected my chain is too short since the gap betw RD upper pulley &chain is much larger than the 8-15mm (specified by campy for correct chain length). It is about 21mm.
3. So i bought a new chain. When trying to fit the new chain, i found that it is not a chain length problem. My old chain is already the longest usable length! Anything longer and the chain becomes sagged at the small-small combination.
4. When shifted to small-small combination, the RD seems to be already limited by the 2 pieces of metal as shown in the photos. In my case these 2 pieces of metal are in contact (1st photo).
5. I took a photo of a friend's bike using 11s mechanical super record with 12-29T and short cage as well. There is a gap in between the 2 pieces of metal. Shifting to big-big is also not a problem in his case (2nd photo with arrow showing the gap).
My question is why is it not possible to shift to the big-big combination and how do i resolve it? Is it because the rd is not able to spring back (as limited by the mechanical contacts) to absorb a longer chain or something else?

Since the slope is >25% and probably 12-29T may not be sufficient for me, i might possibly buy a medium cage and also lengthen the chain to accomodate a 11-32T or 12-32T cassette. How do i do that with the above problem?
Attachments
No gap.jpg
gap.jpg

joeyb1000
Posts: 236
Joined: Thu Mar 03, 2016 8:37 pm

by joeyb1000

Can you post a side photo of the rear derailleur in the small chainring and smallest cog?

by Weenie


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ultimobici
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by ultimobici

To your last question about a change of cage to accommodate a 12-32, don’t bother. Cage length has nothing to do with largest possible sprocket size.


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BdaGhisallo
Posts: 2369
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

ultimobici wrote:
Fri Jan 03, 2020 6:41 pm
To your last question about a change of cage to accommodate a 12-32, don’t bother. Cage length has nothing to do with largest possible sprocket size.


Sent from my iPhone using Tapatalk
Directly no, in that the angle the RD moves down across the cassette is governed by the geometry of the RD movement and that determines how large a cassette cog you can run for the lowest gear, but surely a larger rear cog size spread (along with the tooth size difference between chain rings) requires more chain wrap capacity from the RD and longer pulley cages take up more chain slack.

graeme_f_k
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by graeme_f_k

BdaGhisallo wrote:
Fri Jan 03, 2020 7:14 pm
ultimobici wrote:
Fri Jan 03, 2020 6:41 pm
To your last question about a change of cage to accommodate a 12-32, don’t bother. Cage length has nothing to do with largest possible sprocket size.


Sent from my iPhone using Tapatalk
Directly no, in that the angle the RD moves down across the cassette is governed by the geometry of the RD movement and that determines how large a cassette cog you can run for the lowest gear, but surely a larger rear cog size spread (along with the tooth size difference between chain rings) requires more chain wrap capacity from the RD and longer pulley cages take up more chain slack.
You are correct that a longer cage allows more chain wrap but more chain wrap is not what defines the largest sprocket a RD can accommodate.

The geometry of the RD + the geometry of the hanger decides the largest sprocket size.
Chain wrap is a totally different issue.
Hence - all the Campag 10s RDs "post 2012" shape, for instance, could, hanger geo permitting, accommodate up to a max 30T largest sprocket - but they were made in short and medium cage format to accommodate double (max 16T difference) and triple (max 22T difference) cranksets.

The 11s RD that the OP has, is within it's design parameters with a 16T front difference and 12-29 ... there are plenty of EPS systems out there running that combination.
I have run that combination on the pre 2015 mechanical RD (same geo as the 11s EPS RD) myself on a Merckx 3XM, 408mm stays and 70mm bracket drop, so, within 4mm of effective chain length, the same as the Pina - and have set up plenty of bikes running those sprocket and ring sizes on 11s EPS with no problems. Our early EPS demo bikes back in the days of the Dogma 65.1 Think 2.0s were on 12-29 and 50x34 for that matter.

I'd suspect something different awry.

Are you running the original Pina hanger?
Inside the Pina hanger, is a set screw designed to allow you to adjust the effective hanger hook angle - it may be that this is incorrectly positioned.
If it's a third party hanger, the hook itself, that defines the rear derailleur spring tension for any given degree of extension for the RD, might be incorrectly positioned.

Is the bushing at the top of the RD the correct bushing - has the top pivot bolt ever been changed? The upper bushing, which carries the two "hooks" that limit the rotation of the gear about it's top pivot and the rotation of the gear about the hanger, differs between models. If the TPB nhas been changed ar some time, it's possible that if the bushing was renewed, the wrong one was used.

Is the bushing complete? I had a problematic RD sent to the workshop recently where the frame engagement hook had sheared off (out of spec hanger radius had fractured the forging).

Is the big-big issue that the RD won't make the shift because there in't enough chain, or is the issue that there is something else physically limiting the travel of the RD? H screw setting? Normally a badly set H Screw (inadequately wound "out" for the 29, where it'll need to be on or near it's limit), won't prevent the shift, it'll go with a lot of clatter, because the RD cage and / or top jockey could be coming into contact with the larger sprockets.

Yes, 12-29 on 50/34 is on the design limit - but it works under all normal circumstances, so something is "off".
A Tech-Reps work is never done ...
Head Tech, Campagnolo main UK ASC

PINARELLOF8
Posts: 4
Joined: Wed Jan 01, 2020 4:52 am

by PINARELLOF8

joeyb1000 wrote:
Fri Jan 03, 2020 6:16 pm
Can you post a side photo of the rear derailleur in the small chainring and smallest cog?
Sure ... here are some photos before i took the chain off : small-small (shown with a 8mm hex) and an old photo i think if i enlarged it, it should be in small-small combi as well.
Attachments
8mm hex.jpg
DSC02769 (2).JPG

PINARELLOF8
Posts: 4
Joined: Wed Jan 01, 2020 4:52 am

by PINARELLOF8

Are you running the original Pina hanger?
Inside the Pina hanger, is a set screw designed to allow you to adjust the effective hanger hook angle - it may be that this is incorrectly positioned.
If it's a third party hanger, the hook itself, that defines the rear derailleur spring tension for any given degree of extension for the RD, might be incorrectly positioned.

Is the bushing at the top of the RD the correct bushing - has the top pivot bolt ever been changed? The upper bushing, which carries the two "hooks" that limit the rotation of the gear about it's top pivot and the rotation of the gear about the hanger, differs between models. If the TPB nhas been changed ar some time, it's possible that if the bushing was renewed, the wrong one was used.

Is the bushing complete? I had a problematic RD sent to the workshop recently where the frame engagement hook had sheared off (out of spec hanger radius had fractured the forging).

Is the big-big issue that the RD won't make the shift because there in't enough chain, or is the issue that there is something else physically limiting the travel of the RD? H screw setting? Normally a badly set H Screw (inadequately wound "out" for the 29, where it'll need to be on or near it's limit), won't prevent the shift, it'll go with a lot of clatter, because the RD cage and / or top jockey could be coming into contact with the larger sprockets.

Yes, 12-29 on 50/34 is on the design limit - but it works under all normal circumstances, so something is "off".
[/quote]

Yes... original Pina hanger (photos below); Do you think it's position correctly? I also have another photo of the RD position at the smallest cog

I didn't change anything...from the attached photos, could you tell anything wrong or anything had been changed (w/o my knowledge)?

The upper bushing, which carries the two hooks" that limit the rotation of the gear about it's top pivot and the rotation of the gear about the hanger"
May i know where are the bushings you are refering to?

As for the H screw, i adjusted to 5-7mm as required by campy in the small chainring-big cog combi
Attachments
hanger rear.jpg
small cog.jpg

PINARELLOF8
Posts: 4
Joined: Wed Jan 01, 2020 4:52 am

by PINARELLOF8

graeme_f_k wrote:
Sat Jan 04, 2020 4:10 am
BdaGhisallo wrote:
Fri Jan 03, 2020 7:14 pm
ultimobici wrote:
Fri Jan 03, 2020 6:41 pm
To your last question about a change of cage to accommodate a 12-32, don’t bother. Cage length has nothing to do with largest possible sprocket size.


Sent from my iPhone using Tapatalk
Directly no, in that the angle the RD moves down across the cassette is governed by the geometry of the RD movement and that determines how large a cassette cog you can run for the lowest gear, but surely a larger rear cog size spread (along with the tooth size difference between chain rings) requires more chain wrap capacity from the RD and longer pulley cages take up more chain slack.
You are correct that a longer cage allows more chain wrap but more chain wrap is not what defines the largest sprocket a RD can accommodate.

The geometry of the RD + the geometry of the hanger decides the largest sprocket size.
Chain wrap is a totally different issue.
Hence - all the Campag 10s RDs "post 2012" shape, for instance, could, hanger geo permitting, accommodate up to a max 30T largest sprocket - but they were made in short and medium cage format to accommodate double (max 16T difference) and triple (max 22T difference) cranksets.

The 11s RD that the OP has, is within it's design parameters with a 16T front difference and 12-29 ... there are plenty of EPS systems out there running that combination.
I have run that combination on the pre 2015 mechanical RD (same geo as the 11s EPS RD) myself on a Merckx 3XM, 408mm stays and 70mm bracket drop, so, within 4mm of effective chain length, the same as the Pina - and have set up plenty of bikes running those sprocket and ring sizes on 11s EPS with no problems. Our early EPS demo bikes back in the days of the Dogma 65.1 Think 2.0s were on 12-29 and 50x34 for that matter.

I'd suspect something different awry.

Are you running the original Pina hanger?
Inside the Pina hanger, is a set screw designed to allow you to adjust the effective hanger hook angle - it may be that this is incorrectly positioned.
If it's a third party hanger, the hook itself, that defines the rear derailleur spring tension for any given degree of extension for the RD, might be incorrectly positioned.

Is the bushing at the top of the RD the correct bushing - has the top pivot bolt ever been changed? The upper bushing, which carries the two "hooks" that limit the rotation of the gear about it's top pivot and the rotation of the gear about the hanger, differs between models. If the TPB nhas been changed ar some time, it's possible that if the bushing was renewed, the wrong one was used.

Is the bushing complete? I had a problematic RD sent to the workshop recently where the frame engagement hook had sheared off (out of spec hanger radius had fractured the forging).

Is the big-big issue that the RD won't make the shift because there in't enough chain, or is the issue that there is something else physically limiting the travel of the RD? H screw setting? Normally a badly set H Screw (inadequately wound "out" for the 29, where it'll need to be on or near it's limit), won't prevent the shift, it'll go with a lot of clatter, because the RD cage and / or top jockey could be coming into contact with the larger sprockets.

Yes, 12-29 on 50/34 is on the design limit - but it works under all normal circumstances, so something is "off".
Thanks for the comments...See my post above on your quesitons. I do not know where is the set screw to adjust the hanger. From the photo posted, is my RD installed correctly?

graeme_f_k
Shop Owner / Manufacturer
Posts: 404
Joined: Mon May 26, 2008 12:21 pm
Location: UK
Contact:

by graeme_f_k

PINARELLOF8 wrote:
Sat Jan 04, 2020 3:25 pm
graeme_f_k wrote:
Sat Jan 04, 2020 4:10 am
BdaGhisallo wrote:
Fri Jan 03, 2020 7:14 pm
ultimobici wrote:
Fri Jan 03, 2020 6:41 pm
To your last question about a change of cage to accommodate a 12-32, don’t bother. Cage length has nothing to do with largest possible sprocket size.


Sent from my iPhone using Tapatalk
Directly no, in that the angle the RD moves down across the cassette is governed by the geometry of the RD movement and that determines how large a cassette cog you can run for the lowest gear, but surely a larger rear cog size spread (along with the tooth size difference between chain rings) requires more chain wrap capacity from the RD and longer pulley cages take up more chain slack.
You are correct that a longer cage allows more chain wrap but more chain wrap is not what defines the largest sprocket a RD can accommodate.

The geometry of the RD + the geometry of the hanger decides the largest sprocket size.
Chain wrap is a totally different issue.
Hence - all the Campag 10s RDs "post 2012" shape, for instance, could, hanger geo permitting, accommodate up to a max 30T largest sprocket - but they were made in short and medium cage format to accommodate double (max 16T difference) and triple (max 22T difference) cranksets.

The 11s RD that the OP has, is within it's design parameters with a 16T front difference and 12-29 ... there are plenty of EPS systems out there running that combination.
I have run that combination on the pre 2015 mechanical RD (same geo as the 11s EPS RD) myself on a Merckx 3XM, 408mm stays and 70mm bracket drop, so, within 4mm of effective chain length, the same as the Pina - and have set up plenty of bikes running those sprocket and ring sizes on 11s EPS with no problems. Our early EPS demo bikes back in the days of the Dogma 65.1 Think 2.0s were on 12-29 and 50x34 for that matter.

I'd suspect something different awry.

Are you running the original Pina hanger?
Inside the Pina hanger, is a set screw designed to allow you to adjust the effective hanger hook angle - it may be that this is incorrectly positioned.
If it's a third party hanger, the hook itself, that defines the rear derailleur spring tension for any given degree of extension for the RD, might be incorrectly positioned.

Is the bushing at the top of the RD the correct bushing - has the top pivot bolt ever been changed? The upper bushing, which carries the two "hooks" that limit the rotation of the gear about it's top pivot and the rotation of the gear about the hanger, differs between models. If the TPB nhas been changed ar some time, it's possible that if the bushing was renewed, the wrong one was used.

Is the bushing complete? I had a problematic RD sent to the workshop recently where the frame engagement hook had sheared off (out of spec hanger radius had fractured the forging).

Is the big-big issue that the RD won't make the shift because there in't enough chain, or is the issue that there is something else physically limiting the travel of the RD? H screw setting? Normally a badly set H Screw (inadequately wound "out" for the 29, where it'll need to be on or near it's limit), won't prevent the shift, it'll go with a lot of clatter, because the RD cage and / or top jockey could be coming into contact with the larger sprockets.

Yes, 12-29 on 50/34 is on the design limit - but it works under all normal circumstances, so something is "off".
Thanks for the comments...See my post above on your quesitons. I do not know where is the set screw to adjust the hanger. From the photo posted, is my RD installed correctly?
Sorry for the very late reply, I've not logged on for a while, we've been pretty busy.

Looking at that hanger, it doesn't appear to have the small pitch screw - normally you can see it, it runs at 90 deg. to the flat surface of the hook that the bushing comes up against. I thought all Pina hangers had them but obviously I am wrong ... :-D

The bushing with the two hooks I was referring to is the bronze-coloured pice between the body of the rear derailleur and the hanger - it has two hooks, one of which limits the rotation of the derailleur around the hanger, the other one of which limits the rotation of the dearilleur around it's own top pivot bolt. As it's EPS (sorry, should have picked that up fromk your OP), it's most unlikey this has been changed or modified because that's a Service Centre Only job - Campagnolo don't allow the sale of the bushing, nor supply the tool required to fit a new top pivot bolt (the old one usually has to be drilled out) to anyone other than their main Service Centres.

If the big sprocket / small ring clearance is correct from the teeth of the biggest sprocket to the top jockey, how id you get the RD to that position? Were you pushing it manually in Ride Back Home mode? If so, it may be that the low limit screw (the only mecahnical limiter in the system) is set just a little too aggressively - your can probably flex the RD enough pushing it across with your hand, to effectively "beat" the limit screw and get the biggest sprocket to engage but on the big chainring, especially, if the limit screw is screwed in even a lttle too far, especially on an older mech which is starting to wear a little, it may not allow the RD to shift to the biggest sprocket when fully crossed. I do come across systems from time to time where the RD will go to the biggest sprocket on the small ring OK but not on the large. Usually atweak of 1/4 to 1/2 a turn on the limit screw is enough to fix the problem.

Older RDs can get a little sloppy on the upper pivot, especially if mineral oil is used for lubrication or volatile degreasers or aerosol degreasers are used. Inside the top pivot assembly are two o-rings that seta small amount of angular "float" in the RD. If these get too impregnated with mineral oil, they soften and become "baggy" allowing the RD to hang at an angle to the hanger - so even though the hanger is straight, the top jockey is not held where it should be by the derailleur - again, esp on the big ring, that can lead to laggy shifting or the inability to shift. If that is the problem, we can service the top pivot assemby - as I mentioned, that is a Service Centre only job - normal cost with a full check over and clean on the RD is £46.00 inc. return to you.
A Tech-Reps work is never done ...
Head Tech, Campagnolo main UK ASC

by Weenie


kode54
Posts: 1699
Joined: Tue May 23, 2006 9:39 pm

by kode54

Not to say that this might be your problem, but are you certain the cassette is keyed in correctly? My experience when I had my Campy cassette on one of my wheels, the last cog wasn't keyed in correctly and hence, the cassette was slight ajar and low and behold, I had shifting issues. At times, it was erratic and not consistent shifting. I didn't realize it was that...and stripped the entire drivetrain and put it back and had the same issue (since I didn't even consider the cassette). Just something to check just in case.
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