Help! Campagnolo Record 11 crank ghost shift in small-small combo

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Calnago
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by Calnago

Ok. Now it sounds like you're about to do some very bad things. Do not put the wavy washer on the drive side! Like @spookyload says, you will not be able to get the c-clip in, and there will be potential for way more lateral play. Not good. Edit: actually you mentioned you are using a Praxis conversion kit which I'm not sure if it even uses the c-clip. Does it?
Also, adding spacers between the shell and the drive side cup is a very bad idea as well. If you already have a shell that is say exactly 68mm, you have only a maximum of 0.8mm of tolerance to play with, so if you do add a spacer I'd make damn sure it's not any thicker than that. Reason is that if you creat a width greater than 68.8mm between the cups then it may be impossible for the two crank halves to mate as solidly as they need to at the hirth joint. And that would seriously compromise the integrity of the system.
Of course, if your BB is significantly undersize (less than 67.2mm), then it would be OK to add enough spacers (in fact I'd recommend it) to get the width at least within spec.
Ultimately you really need to figure out the cause of the seemingly inboard chainline, or if the chainstays are simply too short for proper operation.
To say you are using your equipment incorrectly and it's your fault is silly. While cross chaining should certainly be avoided, if properly set up you should be able to run ANY combo without issue. Providing everything is within spec. And something definitely sounds amiss here. It is one thing for the chain to maybe lightly braise the lift pin on the big ring when cross chained small small, but you describe a reproduceable situation where it catches significantly enough to cause a shift. And I don't think filing down the lift pins is an acceptable solution either. In so doing you're damaging one part in order to compensate for something that's not right somewhere else.
Edit: after writing the above I remember you are using a PF30 conversion so some of what I refer to above is obviously relating to a threaded BSA BB of 68mm nominal width. However, the principal is still kind of the same. Hope it makes sense.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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Birdman
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by Birdman

Calnago wrote:To say you are using your equipment incorrectly and it's your fault is silly. While cross chaining should certainly be avoided, if properly set up you should be able to run ANY combo without issue. Providing everything is within spec...


Agree, and thanks reading my thoughts out loud! What prompted me to ask the Weenies for help, is that I've had a quiet drivetrain once, with a Specialized BB30 crank pair with Praxis chainrings. Also, never had problems with Ultegra 6800 cranks, although not on this particular bike.

Also, thanks for stopping me for doing anything stupid. I forgot about the c-clip issue. Yes, Praxis conversion BB still uses the campy c-clip. I don't think I'll be messing with the chainline anymore since my big-big is also a stretch. For now, I'll focus my attention on component quality before I investigate the chainline any further.

I got new Record 11 chain on the way. I'll put them on along with my NIB Athena crank. If that doesn't minimize the issue, then... TBD.
Cervelo R3 MUD ~ viewtopic.php?f=10&t=136544
Specialized Allez Gold ~ viewtopic.php?f=10&t=134419

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Calnago
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by Calnago

Did I miss the part where you said the big big combo is also an issue. Hmmm... If it's a stretch on both sides of the cassette when crosschained I'm inclined to think that the chainstays are really short, maybe less than 405mm? Strange.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

Birdman
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by Birdman

The big-big 50/28 isn't actually causing problems. It is just very noisy and looks like the chain is stretch to near its limit.
Cervelo R3 MUD ~ viewtopic.php?f=10&t=136544
Specialized Allez Gold ~ viewtopic.php?f=10&t=134419

Birdman
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by Birdman

Hi All, a quick update:

So my parts arrived, and I finally had the time to get them installed.

- Campagnolo Athena Carbon 11 50/34, brand new
- Campagnolo Record 11 chain, brand new
- Teflon lube, lots and lots of them!

Once installed, I took the bike on some "parking lot" test ride around the neighborhood, the noise is still audible when I'm in the small-small combo. Although it does feel like the situation improved. It no longer feels like that the big chainring will want to drag the chain up to it in the small-small combo. Not perfect, but good enough for now. I'm going to leave my drivetrain as is and stop pursuing further refinement. I guess I'm ok with just "good enough".
Cervelo R3 MUD ~ viewtopic.php?f=10&t=136544
Specialized Allez Gold ~ viewtopic.php?f=10&t=134419

AZK
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by AZK

Birdman wrote:Background:
- I had Specialized crank with Praxis 48/36 rings


I notice you had a 48/36 before. The big ring on this combo would be much easier to clear when riding cross chain as the difference in teeth/diameter of both rings is less = 12teeth.

If you want to keep the 50 maybe its worth going for a 38t inner to simulate the above chain line. If you would like to keep your smaller gears maybe just try a 36t and see if it works. (a 12-29 cassette is always an option.)

EDIT: I just realised that my suggestion probably only works if the big ring is reduced in size, as the chain leaves the small ring at TDC or just slightly towards the back of that. 34 to 36 might make very little if no difference?

you could maybe slightly shave down the shift pin?

With all the above being said, maybe the ghost shift is a good thing. Dragging a chain across the side of your teeth can waste big watts and destroy parts. Tony Martin rides a 58t on his TT bike so he can avoid the 11t and stay higher up the block (probably also so the chain doesn't need to go around a really tight 11t radius)

Birdman wrote:pursuing further refinement

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Miller
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by Miller

I don't get why the OP even cares about the small-small combo, far less goes to such effort to 'cure' the problem, it's the least useful gear combination there is.

Birdman
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by Birdman

Miller wrote:I don't get why the OP even cares about the small-small combo, far less goes to such effort to 'cure' the problem, it's the least useful gear combination there is.


I fully agree with you. I don't use small-small often and when I do, I shift away from it. That's the thing, I do use it, even though I use it probably 3% of the time, but I'm still on it every once in a great while. And when that happens, I don't want to have issues with it.

I just finished building my Cervelo R3 MUD, with 5mm longer chainstay, Ultegra 6870 Di2, with Ultegra 6800 50/34 crank, 11-28 cassette, mid-cage derailleur. It is PERFECT. It was easy to set up, and it is easy to set it up noise free! Shimano sets the standard for me, and I expect all my bikes to perform the same, all 22 gears.
Cervelo R3 MUD ~ viewtopic.php?f=10&t=136544
Specialized Allez Gold ~ viewtopic.php?f=10&t=134419

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Calnago
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by Calnago

Yes, just because it's not a good combo to be in, does not mean it shouldn't be working. That's like the doctor office joke where you go in and say 'It hurts when I do this" and the doctors advice is "well don't do that then".
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

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