Campagnolo Rear Derailleur 2015+ Upper Pivot

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joeyb1000
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by joeyb1000

graeme_f_k wrote:
We need to do a medium-to-long term field test simply because the new ratchet effectively "over-winds" the springs slightly, so is a departure from their original designed specification. We don't want to rush out there and say "do this" then discover that it's cost a lot of riders riding time because of failures caused by an unintended consequence ....

The issue is caused by the C60 hanger having a greater "kick" backwards (to facilitate easier removal of the rear wheel with fatter tyres, without changing chainstay length), so displacing the effective centre around which the jockey cage turns further back - the solution that we are proposing changes the balance of the upper and lower tension springs (B and H) to draw the RD back under the cassette to where it's intended to be and to help the RD to again track the cassette correctly.
...


What I noticed when I tightened up the H screw was that it caused a lot of chain tension. That seemed to cause a lot of extra drag in the drivetrain ( a lot more than the $millions spent on ceramic bearings).

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by graeme_f_k

joeyb1000 wrote:
graeme_f_k wrote:
We need to do a medium-to-long term field test simply because the new ratchet effectively "over-winds" the springs slightly, so is a departure from their original designed specification. We don't want to rush out there and say "do this" then discover that it's cost a lot of riders riding time because of failures caused by an unintended consequence ....

The issue is caused by the C60 hanger having a greater "kick" backwards (to facilitate easier removal of the rear wheel with fatter tyres, without changing chainstay length), so displacing the effective centre around which the jockey cage turns further back - the solution that we are proposing changes the balance of the upper and lower tension springs (B and H) to draw the RD back under the cassette to where it's intended to be and to help the RD to again track the cassette correctly.
...


What I noticed when I tightened up the H screw was that it caused a lot of chain tension. That seemed to cause a lot of extra drag in the drivetrain ( a lot more than the $millions spent on ceramic bearings).


You will get extra tension, it's true - however it's an insignificant addition to chain drag. The losses in chain drag in the real world are so infintesimal (despite what the propaganda says) that I'd not worry about it too much. In any case, moving the H screw is doing exactly the same thing as adjusting the B screw in Shimano-world - whatever you do to move the top jockey away from the cassette will lead to a rise in chain tension because you are only offsetting one spring's tension against another.
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jwfinesse
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by jwfinesse

On my Pegoretti, I couldnt get my 2015+ SR rear mech to work properly. I did everything I could possibly think of, including the 1kg test, which my rd passed with ease.

To eliminate rd as a source of error, I bought a brand new 2015+ SR rear derailleur, and compared to my old (still 2015+) rd, it has a different ratchet wheel on the pulley cage. Still three holes for the pivot spring, but the teeth portion's length increased substantially. On my previous rd, I had to use the hole which gave me the highest tension, and even with the h-screw cranked all the way in, cassette to pulley distance was about 1cm. Now, i can get less than 4 mm if I crank that sucker tight (tension hole still on the highest setting) Now I can adjust it to 4-6mm which is Campy recommended.

I guess Campy made a running change on the rd.

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Calnago
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by Calnago

Did you actually remove the ratchet wheel of both derailleurs and set them side by side to compare? A picture of the two would be so great. Did you use the same chain etc, exactly the same length as it was prior? When you put the spring in the hole that provided the most tension, are you absolutely certain that was the hole that in fact allowed for more tension and not less? It took me a while to figure out exactly which hole that was. What size cassettes were you working with? I ask these questions because I've not heard anything about this running change you mention. Of course, a picture of the two ratchet wheels would be the simplest and clearest way to show us the difference.
Also, in your post you say you couldn't get your rear derailleur to work properly. What exactly was it that wasn't working properly?
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jwfinesse
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by jwfinesse

Left one is the changed ratchet, right one is the previous. The teethed portion on the ratchet increased alot. And from the looks of it, the holes remain on the same position.

I've taken my rear derailleur apart at least a dozen times, so I know which hole gives me higher/lower tension. The leftmost hole gives the highest, while the farthest hole on the right gives the least.

The problem I was facing was the pulley-to-cassette distance was much greater than campy recommendation, which gave me a sluggish shifting at best with 11-27 cassette. With the stock tension set-up, the distance was almost an inch away. I measured and found out Pegoretti hanger exceeds the campy spec for hangers, which is why I had this problem in the first place. So i guess the frame is to blame here. But then, I still needed to make them work together somehow.

With 11-25 cassette, it was definitely a no-go. On 11-27, trouble persisted on the 4th to 5th cog movement both up and down (counting from the smallest). I own derailleur hanger tool, so I had my hanger straightened down to .5mm, and as I mentioned above, cable friction was not an issue. So I came to the conclusion that either the derailleur or the shifter is at fault here. Tried the derailleur first, since it's so much easier to set up compared to the shifters.

Now the pulley-to-cassette distance on 11-27 can be adjusted to a point where I feel they are 'too' close. Distance on 11-25 would be just perfect when cranked to the max.

Haven't test ridden it yet to see how it shifts under load, but it shifts just fine on the stand, whereas the previous SR rd gave me trouble even on the stand.
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Calnago
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by Calnago

That's great info @jwfinesse... and thanks for the pictures... definitely different designs. And thanks also for the clear explanations and answers to my questions.

I spent a lot of time on this issue when building my C60. I was kind of expecting some issues when building the C60 given what some have said in this thread, including myself, and was actually looking forward to experiencing the issues, and a fix hopefully, as I did the build. In fact, I took the time to check the hanger specs and compare them to Campy's spec, and found them to be within the specs. My derailleur had the ratchet on the right, the one I'm familiar with. I installed it with no changes to begin with and it worked, although it was a little further away from the cassette than I would have liked. So all I did was move the spring to the high tension hole (and indeed you are correct, it's the one on the left) and all was good. I experimented with different chain lengths and found that a chain on the longer side of their recommendations was better than a chain on the shorter side. But with that one simple change, moving the spring from the middle hole (how it came), to the higher tension hole, I was able to get the chain within spec on all cassettes ranging from 11/23 right on up to 11/29. In fact, on the 11/29 I have to back the tension off some otherwise the pulley and cassette teeth jam they are so close. Even on the 11/23 I am able to get it to within probably 4-6mm of the 23 cog. So all was/is good. I've got pictures of all this as well, and need to post them up here so it's believable.

But thanks for posting that difference in the ratchet teeth mechanism. Do you happen to remember which hole the derailleur spring was installed in from the factory?
Also, were you able to ascertain where your hanger on the Pegoretti was actually out of spec according to Campy's diagram?
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jwfinesse
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by jwfinesse

I don't have means to measure the sweep or the curvature value r, but the Pegoretti hanger was close to 30~31mm long. It's not easy to measure the exact center lines of two empty holes in the dropout and hanger mount hole, so my measured length is on the conservative side. But it's definitely good 2~3mm longer than Campy's spec.

I didn't know if that 2~3mm difference can drastically deteriorate shifting, but I guess it did.

Oh, and I believe the factory tension hole setting was in the middle.
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hangerspec.jpg

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Calnago
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by Calnago

So... I've been meaning to post my findings relating specifically to the Colnago C60 and the new Campagnolo rear derailleurs. I used my own C60 to test things out and measure the details. It's a size 59 Traditional.

Quick Summary and Conclusions:
1) The Colnago C60 rear derailleur hanger is within the Campagnolo Specifications.
2) I was able to adjust it perfectly for all cassette ranges the derailleur is designed for, tested on 11/23, 12/25, 12/27, 11/29 cassettes. In all cases I could adjust the derailleur so that the upper pulley was within 5mm of the sprocket teeth. In fact, on the 11/29 cassette I had to back off the tension otherwise the pulley was too close to the largest sprocket. Might be the same on the 11/27 although I didn't specifically ride with this cassette yet... but thoroughly tested the extreme ranges using 11/29 and 11/23 cassettes to verify things.
3) The only modification I made was to move the tension spring for the cage from the middle hole (factory setting) to the highest tension hole.

Here's a pic of the highest tension hole (highlighted in white) that I moved the spring arm to...
Image


Next I wanted to satisfy myself that the Colnago C60 derailleur hanger is in fact within Campagnolo's specifications for derailleur hangers. Note that Colnago definitely made use of the maximum boundaries of the guideline choosing a 28mm distance from the axle center to the derailleur bolt center, and is right on the limit of the 35 degree tab spec. This makes for relatively easy wheel changes compared to some other hangers....

Campagnolo Specs...
Image


Colnago C60 Hanger Specs... as close as I could measure, using actual hanger and frame dimensions. Where there might have been some question as to the accuracy of my measurements, I erred to the side that would throw it out of specification rather than try to fudge it to "make it fit".
Image


Chain length was established first... I found that a chain on the longer side was better than one on the shorter side of the specs. As such, I can just pass (barely) a 10mm allen key between the chain and the lower portion of the cage surrounding the lower pulley when the chain is positioned on the smaller chainring (36 in this case) and the smallest sprocket (11 in this case).


Ok... next up... pics of the install showing the distance from the largest sprocket to the upper pulley. I did this exercise for the following cassettes...(11/23, 12/25, 12/27, 11/29)....just to make sure that they all would work. The pics below just show the 11/23 cassette.


Below are progressive closeups up of the distance between the teeth of the largest sprocket on the cassette and the upper pulley of the derailleur when the chain is on the largest sprocket and the smallest chainring up front. In this case, the chain rings are 36/52 and the cassette is the smallest, and most likely to create difficulty with this adjustment, that Campy currently makes... 11/23.

Firstly, an overview of the setup (36/52 chainrings and 11/23 Cassette)...
Image

Next... a little closer, but same setup...
Image

And finally... super closeup so you can really get a feel for just how close the pulley is to the sprocket...
Image

The above pics just show the 11/23 cassette as it requires the derailleur to be closer than any of the other cassettes. In fact, when using the 11/29 cassette I have to back off the tension otherwise the upper pulley gets too close to the sprocket and causes binding and noise.

So, there you have it. I also set it up initially with no change in placement of the tension spring in the derailleur, and while it was probably acceptable, I could not get it quite as close as I show in the pictures above without the change, but it certainly would have been usable. In any case, it certainly wasn't anywhere close to an inch away from the sprocket... maybe more like 10mm rather than the 5-7mm the guidelines would like it to be. And even though the Campy docs state that for the 11/23 cassette, it may not be possible to get the gap smaller than 7mm, I was able to get it significantly smaller than that, as the pics indicate. Certainly no more than 5mm.

I think the big takeaway from this, for me at least, is that the derailleur hanger on the C60 is within Campagnolo's spec and that with proper install things work as they should. And given what the previous poster @jwfinesse just showed... that there may have been a running change in the toothed wheel that adjusts the cage tension, I suspect that it will be even easier to achieve the proper tension here in the future, without even having to move the spring to the high tension hole like I did here.
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JKolmo
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by JKolmo

Thanks for this guys! I just moved my SR 2015+ spring to the high tension hole on my Extreme C. A lot snappier shifting and a closer gap to the largest cog! Will do the same on my C60. Kudos to you!

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JKolmo
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by JKolmo

...and also it makes more sense to have higher tension in the RD when running a 34-50 compact as I do on my Extreme C. Not getting chainstay chain slaps as easy now, almost like having an mtb like RD clutch.

wobbly
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by wobbly

Do the spring tension holes exist on 2009 SR RD ?
This could explain some shifting issues on my ExC too

Thanks and all the best for the new year to all

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Calnago
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by Calnago

@wobbly: I'm presuming you're talking about first generation 11speed? On the first generation of 11spd, there were only two holes for the spring tension. Then, when they came out with the 12/29 cassette, they added a third, but that hole would be irrelevant to a situation where you wanted to get the pulleys closer to the sprockets, versus farther away which was needed in some cases to accommodate the 12/29 cassette. So, if you were to pull yours apart, and find two holes, you will also probably notice that the spring is in the hole furthest to the right, which would correspond to the middle hole in the pics above. So, you could certainly try moving the spring to the other hole further to the left (same one I have highlighted in white above) and that should help a bit, providing the reason you're doing it is to get the pulleys closer to the largest sprocket at the back when the chain is on the smallest chain ring up front. But if you've already managed to achieve a relatively close distance, then I doubt changing the spring would help. In fact, it might just mean you have to back it off with the adjusting screw in order for it to now jam into the sprockets, effectively bringing it back to where you had it in the first place.
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3Pio
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by 3Pio

As first, i wish u a Happy New Year to everyone on this forum.A lot of nice rides, to shade as much weight as possible, a lot of happiness and joy in the new 2017 :)

I just found this thread, and seem that solve the problem i had with my Rear Der. (C60 50S, 52/36 - 11-29). It's working in one range of the cassette, then on the smallest part of the cassette does not work very well.. If i adjust upshift to work properly, then downhift sucks sometimes. Finally i adjusted somehow to be in usefull form, but stil far from ideal.

Before i disassemble my rear der (Record 2015), does this fix with the spring hole work with 11-29 cassette? Or if i switch to the hole on the left, there will be to close position for 11-29?

Thanks :)

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Calnago
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by Calnago

@3Pio: I am actually running an 11/29 cassette currently on my C60. But I used the 11/23 for this testing because if you can get that setup to work properly then the others are a breeze. It is possible to have the pulleys too close to the 29 cog when you do this but you just back off the tension some with the adjusting screw till it's fine. Chain length can be a factor as well in getting everything dialed.
However, I've seen your build and in your case I'd be inclined to recable your bike as a first step. What you are describing can likely be attributed as much to cable friction as anything else.

Run the cables so that they cross inside the downtube, meaning the derailleur housing from the right shifter enters the downtube on the left side and the housing from the left shifter enters the downtube on the right side. Also, your cable housing is currently too long imo making unnecessary bends along the route. Every bend adds friction, and the bends that are necessary need to be as smooth an arc as possible. It will also tidy things up and look a lot better.
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wobbly
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by wobbly

Thanks for the reply Cal. :beerchug:

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