Missing Link 11 Problem

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rmerka
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by rmerka

Calnago wrote:I don't have a missing link but it would be interesting if someone with a super accurate set of digital Vernier calipers could measure the max dimension of a missing link plate versus a standard plate on a campy or Shimano chain.


All these are new and unused

Largest part of Record 11 plate
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Largest part of Missing Link 11s
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Valley on Record 11
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Valley on Missing Link 11s
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Here they are overlay-ed on each other with the pins lined up. The Missing Link is very asymmetric compared to the symmetry on the Campy. Don't know if that makes much of a difference at all.
Image

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ultimobici
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by ultimobici

Bridgeman wrote:Calnago, thanks for your very kind words. Yes, you are correct, "the chainlink outer plates ride on the ridge of the 11tooth cog that also acts as the spacer between it and the 12 tooth cog". The outer plates of the 11 tooth sprocket are riding on that ridge, rather than the rollers riding in the valleys between the sprocket teeth. I have many many used sprockets showing evidence of this, and some time ago I began modifying the sprockets to provide clearance which yielded new life to the cogs.

Because of the geometry of the Missing Link end plates, the elongated portion, this only exacerbated the problem.

I am still open to the idea that I could be overlooking something, but until that happens I think Campy needs to address this issue. Chains should not be rolling on their end plates as it is not the most efficient way to utilize them. All other cogs have proper clearance, as the chain rollers are engaged with sprocket valleys.

How is this an issue Campagnolo need to address? KMC is the source of the issue, not Campagnolo.


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Bridgeman
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by Bridgeman

ultimobici wrote:
Bridgeman wrote:Calnago, thanks for your very kind words. Yes, you are correct, "the chainlink outer plates ride on the ridge of the 11tooth cog that also acts as the spacer between it and the 12 tooth cog". The outer plates of the 11 tooth sprocket are riding on that ridge, rather than the rollers riding in the valleys between the sprocket teeth. I have many many used sprockets showing evidence of this, and some time ago I began modifying the sprockets to provide clearance which yielded new life to the cogs.

Because of the geometry of the Missing Link end plates, the elongated portion, this only exacerbated the problem.

I am still open to the idea that I could be overlooking something, but until that happens I think Campy needs to address this issue. Chains should not be rolling on their end plates as it is not the most efficient way to utilize them. All other cogs have proper clearance, as the chain rollers are engaged with sprocket valleys.

How is this an issue Campagnolo need to address? KMC is the source of the issue, not Campagnolo.


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I understand your point, and agree that it is a valid one. There are, in my opinion 2 distinct issues at play, and I see I haven't been clear about delineating them.

My Issue 1. The KMC link potentially can become problematic when used on Campagnolo 11 tooth sprocket.

Since this is not the responsibility of Campagnolo, it would not be appropriate for them to address this potential issue, particularly when it is in their best interest to insist that their pin coupling method be used. Completely understandable.

My Issue 2. Under load, the Campagnolo chain (without the KMC link) makes contact with the 11 tooth sprocket ridge.

In my case this contact has caused problems with chain skipping. This has been a problem for me for some time now, well before I began the use of the KMC link.

Update; I now believe I understand what might be causing my skipping issue.

When the chain is in the 53X11 position, it is at an angle. Under load, the chain is being pulled inward, towards the ridge side of the cog, an angular moment.

If there was no angle, and both the 53 and 11 were in the same plane then this normal force condition would more than likely not result in skipping under load.

As mentioned, I have many cogs that clearly show wear marks as a result of this contact. When the chain end plate is making contact then the chain it is not permitted to fully seat into the valley of the 11 tooth cog, causing it to wear prematurely.

In every case when I have made a simple modification for clearance on the 11 cog the skipping was no longer an issue.

Now, introduce the KMC Missing Link. Because of its unique end plate geometry, this exacerbates this situation. But when I modify the cog performance is restored.

I should re-qualify the condition of my 3 cassettes. I claimed they were new, they were not. They have approximately 180 miles on them. All 3 have very slight contact marks in the inner ridge of the 11 cog. The mileage is so low I just considered them to be new. The chain is new however. For reference, chain cleaning and frequent lube is an obsession with me. Usually after every ride.

Photos coming soon.

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Calnago
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by Calnago

Ok, let's review your issue:
You, and you alone, seem to be having this issue, barring cases where the chain and/or cog is simply worn out. What I write below has nothing to do with the KMC link... I don't really care about that. But you also say that there is an issue with the Campy chain and a Campy cog, so this part I wanted to verify myself whether it is an issue or not. With that said...

I have looked very closely at exactly what you are describing with a Campy Record 11sp chain and two 11tooth Campy sprockets (11A), removed so I could really see what was happening clearly from both sides, from both a new Record 11/29 cassette, and an older used 11/23 Super Record cassette from 2011. I wrapped the chain hard around both of these sprockets and tried to create the issue you describe. I could not. The plates are very very close to the channel surface, and perhaps "brush" the surface a teensy bit if you rock the chain, but that's it. Nothing at all that would cause the skipping you describe. I "folded" the chain so I could isolate just one link and center roller and pushed it against the valley of the cogs. Still could not see the problem. I for one am completely satisfied that the cog and chain interface between a Campagnolo chain and an 11tooth Campagnolo sprocket is just fine.
What is puzzling is that you seem to have this problem with "all" your cassettes. How many are we talking about here? And for all intents and purposes the ones that only have 180 miles on them I think we can consider new. You said you got them "cheap". Are you certain they were new, original Campagnolo cassettes? Just verifying a few things.
Lastly, and even you find this odd, is than no one else seems to be having this issue. Don't you think if it was an issue even in the slightest, that every pro sprinter in the world using a Campy drivetrain would have been up in arms over this. You simply would not be able to sprint in confidence if you knew your chain was going to be skipping over the 11tooth cog on a consistent basis.

Now, go back to one of your previous posts where you said you could lessen or increase the skipping issue simply by adjusting your derailleur. Hmmm... sound's like there's something amiss. If it was the cog and chain interface, then how could adjusting the derailleur a bit possibly have anything to do with that, unless the geometry of your frame and derailleur hanger is such that the chain is so far back as it first catches the teeth on the 11 tooth cog that it only engages a few cogs. Check that out... looking at your rear setup and treating it like a clock face (in the large chainring/11 tooth cog), where does the chain first engage the sprocket? Is it closer to the 6 o'clock position or the 8 o'clock position. The closer it is to that 8 o'clock position, the less engagement your chain has on an already small sprocket.
I think you also said that you are in your 11tooth cog a lot. Really? Are you constantly sprinting at 30mph plus, or just like to cross chain a lot? Either way, if this is true, expect the 11tooth cog to wear out fairly quickly... both due to how often those 11 teeth are engaged (compared to say a 25tooth cog), and also from the power since it's likely you'll be sprinting as hard as you can if you're in that gear, causing more wear than if you're just cruising along. And no one I know is just cruising along in their 11tooth cog, unless they're completely cross chained, in which case they would do well to learn how to use their gears more efficiently.

Here's one more troubleshooting thing, since I do think you are diligently trying to get to the bottom of this. I would be too. Have you taken some of your "unmodified" cassettes that are skipping and tried them out on a completely different bike? Do they skip on other bikes as well? Somethings not right with your situation. Don't know what it is, but your chain should not be randomly and consistently skipping like you say it is if all is well.

That's all I got.
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crn
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by crn

Not to resurrect this old topic but I can confirm that KMC missing link has problem wirh 11toth cog on campy chorus 11-29 casette. I recently changed chain from chorus to kmc with missing link and suddenly chain started skipping on 11 cog. I switched to chorus chain with missing link - also skipping. Using chorus chain with campy pin fixed the problem. Same cassette same chain only difference is not using missing link. Just for fun I used dremel to sand down elongated parts of missing link and that also fixed the problem. No skipping on both kmc and chorus chains. Using 12-29 cassette has no problem with missIng link either way.
Last edited by crn on Mon Oct 01, 2018 3:59 pm, edited 1 time in total.

Bridgeman
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by Bridgeman

crn wrote:
Sat Sep 29, 2018 2:38 pm
Not to resurrect this old topic but I can confirm that KMC missing link has problem wirh 11toth cog on campy chorus 11-29 casette. I recently changed chain from chorus to kmc with missing link and suddenly chain started skipping on 11 cog. I switched to chorus chain with missing link - also skipping. Using chorus chain with campy pin fixed the problem. Same cassette same chain only difference is not using missing link. Just for fun I used dremel to sand down elongated parts of missing link and that also fixed the problem. No skipping on both kmc and chorus chains. Using 12-29 cassette has no problems with misisng link either way.
I have used a dremel tool to do the same modification, and it solved the problem. Because of the hassel, I've since gone back to using Campy Chain with pin and no longer have the skipping problem.

As I have mentioned, I have many 11 spd cogs with the missing link wear marks and also cogs where I have dremeled clearance at those points of contacts on the cog to stop the skipping. I didn't dremel the link as I was concerned about weakening it.

I was wrong in saying the Campy needs to address this problem, but if they were to reduce the diameter of the surface in question it would solve the problem.

In the past, before I found what was causing this problem I've had several shops try to fix the skipping. Everything was checked, including hanger position. It was simply the extended shoulder on the missing link that was not allowing the chain to properly seat into the cog. Skipping would only happen under heavy loads, when sprinting for example. It was very aggravating to say the least.

I'll post photos.

Glad you found the same issue and have taken measures to fix it!

crn
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by crn

Bridgeman wrote:
Sun Sep 30, 2018 5:11 pm
I didn't dremel the link as I was concerned about weakening it.
That's why I said 'just for fun' and after confirming that problem was solved I used campy pin to connect the chain NOT the modified missing link.
Bridgeman wrote:
Sun Sep 30, 2018 5:11 pm
In the past, before I found what was causing this problem I've had several shops try to fix the skipping. Everything was checked, including hanger position. It was simply the extended shoulder on the missing link that was not allowing the chain to properly seat into the cog. Skipping would only happen under heavy loads, when sprinting for example. It was very aggravating to say the least.
Yes same here and it drove me nuts :lol: Your post helped me to solve the problem in matter of minutes :thumbup:

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by Bridgeman

crn wrote:
Sun Sep 30, 2018 7:07 pm
Bridgeman wrote:
Sun Sep 30, 2018 5:11 pm
I didn't dremel the link as I was concerned about weakening it.
That's why I said 'just for fun' and after confirming that problem was solved I used campy pin to connect the chain NOT the modified missing link.
Bridgeman wrote:
Sun Sep 30, 2018 5:11 pm
In the past, before I found what was causing this problem I've had several shops try to fix the skipping. Everything was checked, including hanger position. It was simply the extended shoulder on the missing link that was not allowing the chain to properly seat into the cog. Skipping would only happen under heavy loads, when sprinting for example. It was very aggravating to say the least.
Yes same here and it drove me nuts :lol: Your post helped me to solve the problem in matter of minutes :thumbup:
Glad to be of help.
Here are some closeups;
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pdlpsher1
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by pdlpsher1

Wow. I can’t believe a quick link eat a hole through the 11 cog! I’m now using the Shimano version of the quick link on a Dura Ace chain. My group is Shimano so obviously no issues here. Perhaps you can try the Shimano quick link on a Campy group. The Shimano quick link has no protrusions. Here’s a close up pic. of the one I have.

Image


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Bridgeman
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by Bridgeman

For clarification, the second photo shows the contact marks on the cog from the link plates. The third photo shows my dremel mod, which provides clearance and eliminates the interference problem. The result is that the chain will fully rest in the sprocket valleys.

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pdlpsher1
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by pdlpsher1

Got it. I'm not familiar with Campy cassettes but it appears that even without the quick link the chain makes contact with the cog. I assume this is by design due to the larger freehub body?

Bridgeman
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by Bridgeman

The chain plate edges do make contact with the cog shoulder, as shown in photo 2. This has been normal for all of my 11 speed cog over the years.

Notice in photo 2 the faint marks on either side of the wear mark. These are the contact points of the missing link plates and the reason for skipping.

crn
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by crn

I simply dremeled those tiny protrusions from missing link and that fixed the problem. I rode it for a few days without any skipping.

Image

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Calnago
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by Calnago

pdlpsher1 wrote:Got it. I'm not familiar with Campy cassettes but it appears that even without the quick link the chain makes contact with the cog. I assume this is by design due to the larger freehub body?
No. Campy chain, no quick link... no problem. See posts #11 and #19 earlier where I tested this in detail. The outer plates do not make contact with the body (base next to teeth) of the cog. The problem is solely the result of using the quick link and/or using a worn out 11tooth cog/chain far too long.
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Bridgeman
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by Bridgeman

crn wrote:
Mon Oct 01, 2018 9:24 am
I simply dremeled those tiny protrusions from missing link and that fixed the problem. I rode it for a few days without any skipping.

Image
I tried this as well, and was concerned with weakening the plates. The design of the plates is such that there is constant material width around the center pin slot. This will not be the case when modifying it to stop the skipping. In other words, I was concerned with creating a failure potential with the chain during a sprint. That's why I went back to the cog mod solution.

Anyway, it's all moot, as going back to the Campy pin connection takes care of this issue.

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