Chain-suck sucks; any suggestions on chain catchers?

[charliedid]

...make sure chain is not too long and steer clear of small/small.

Clutch derailleur?

[jbay]

Originally Posted by jambee

I think that there are some facts:
1. Super gritty! My god riding in Brandenburg sand does a number in your chain.
2. Crank is brand new.
3. Cassette has some miles on it and us pretty dirty.

What chain were you using?

I ask but I have the same crank and can tell you that the Sugino rings, combined with a SRAM chain, suffered from spectacular chainsuck. Switching to TA rings seemed to address that and rumour has it that Shimano chains suck less too, so to speak.

— John

P.S. I moved that crank to my road bike and use 1x on my bikes that get used in conditions like you describe.

[jambee]

I checked today. The chain is a KMC x11.

[Rusty Luggs]

Originally Posted by ultraman6970

Never had that problem, not even when I was racing. I do understand chain drop from having the FD set a few mm off but from there to get the chain sucked, i cant even explain how it could happen because never happened to me.

https://wickwerks.com/chain-suck/

[DrewK]

I had loads of problems once, with chain suck, that turned out to be a SRAM chain that was unhappy on Shimano rings. The rings were 36/46, with an Ultegra 10 speed group. Had all kinds of issues. It drove me up a wall.... LBS couldn't figure it out, I couldn't figure it out... Switched back to a Shimano chain... issues gone. There are small differences in the chains. I thought they were interchangeable... not so.

Anyway, if you're mixing and matching chains and chainrings... might be something to try.

When I had my issues, I couldn't find a gadget that would fit between the chainstay and the chainrings.

[dddd]

Originally Posted by DrewK

I had loads of problems once, with chain suck, that turned out to be a SRAM chain that was unhappy on Shimano rings. The rings were 36/46, with an Ultegra 10 speed group. Had all kinds of issues. It drove me up a wall.... LBS couldn't figure it out, I couldn't figure it out... Switched back to a Shimano chain... issues gone. There are small differences in the chains. I thought they were interchangeable... not so.

Anyway, if you're mixing and matching chains and chainrings... might be something to try...

Things can definitely be sensitive these days because of parts interchanges between brands. From the Chain efficiency tests that were published, SRAM chain was shown to have tighter clearances (that might more easily cause debris to wedge tightly between the teeth and the chain).
And, on the chain-drop side of things, I imagine that a chain having tighter clearances (such as a new chain) would also bow a bit further inward as it disengaged from the big ring's teeth, relying on greater drive tension to pull the arc more into a straight line that might feed the chain directly onto the small ring's teeth instead of to the inboard side.
From that effect, I believe that maintaining some minimum of drive tension during a front downshift tends to better center the falling chain onto the tips of the small ring's teeth.

While setting up and de-bugging many a road bike, I keep in my arsenal a final adjustment wherein I may rotate the cranks with a half-round file supported alongside and at an angle to the tips of the small ring's teeth, a minor correction (first photo) that so often has cured a bike of the dreaded chain-drop.
I have also beveled the other side of the tips of the teeth (second photo) for cases of the chain tending to fall between the chainrings, with the chain then left skating atop the teeth as if in neutral.

The hard part about such fine-tuning using the file is supporting the file while turning the cranks without the crank hitting your arm, so it helps to use a long file, with it's end resting on a tall-enough block of wood, and one's arm carefully positioned so as to allow the cranks to rotate freely.
Two or three passes of the teeth past the file takes off almost no metal, yet can make a huge difference in shifting reliability.

Sometimes it is a burr on a single tooth of the big ring that can cause chain suck (or on the tip of small ring where it can cause chain drop).
I suspect that running the small ring's teeth past the file corrects all of the teeth's pointy tips into more of a straight line (and biased to whichever side is favorable to a bike's downshifting malady).

These things can happen even to modern components in fresh condition, just as on old bikes having a dog's breakfast of mixed parts.

First photo showing correction of chain drop.
Second photo showing correction of chain falling between rings.

[dddd]

Originally Posted by m_sasso

Actual chain length too long, exceeding the rear derailleur wrap capacity, worn rear derailleur cage spring, improperly adjusted B screw, improper chain line with short chain stays?

Looks to me like the slack in the chain coming off the chain wheel was not taken up quick enough, hit a bump, chain catches large ring, hangs up, chain caught between stay and chain wheel.

This sounds to me like an excellent summary/analysis of what can happen.

[Lewis Moon]

Originally Posted by mktng

Deda Dog Fang. If your bike can accommodate it. Low key. Light weight. More reliable than a K edge. From experience.



Sent from my Mi 9 SE using Tapatalk

Ditto. For chain drop, the old ways are the best.

[jbay]

Originally Posted by jambee

I checked today. The chain is a KMC x11.

Interesting. KMC chains have the reputation of being reasonable with respect to chainsuck. In order of expense, I would suggest trying a Shimano chain and, if that doesn't address the problem, different chainrings. As I mentioned in my previous reply, TA 'rings made a difference for me.

-- John

[Ralph]

Assuming FD is adjusted so cage is real close to small ring maybe even chain barely tickling the cage....(and a large difference in the teeth count doesn't help), in addition to checking some of the things mentioned above.....The first thing I would do is put more tension on the chain...either with B screw or taking a couple links out of chain (assuming it will still wrap big to big).