Chain jamming into chainstay

Chunkers1980

Yes.

The Rookie

Good chance, yes, assuming everything else is working as intended.

BlueAdvocate

As another preventative option; try fitting a stinger for adding tension; think it was Northwind (on his C456) who had this and also placed a bolt through it to make sure if it happened the chain could not find a way through.

The Rookie

But a stinger adds no tension AT ALL and in this case the chainsuck will lift the chain off the stinger, so how it would help is beyond me!

leaflite

The Beginner wrote:

But a stinger adds no tension AT ALL and in this case the chainsuck will lift the chain off the stinger, so how it would help is beyond me!

Having a bolt through the stinger but above the chain would stop it from coming off the stinger.

Have you tried a more aggressively ramped middle ring, such as xt?

the_moodster

cyd190468 wrote:

Does it still happen if you ditch the bash guard? Maybe it's too close to the big ring.

This

BlueAdvocate

The Beginner wrote:

But a stinger adds no tension AT ALL and in this case the chainsuck will lift the chain off the stinger, so how it would help is beyond me!

Does it not? really? I would suggest that's how its fitted. Yes you can measure the chain over the stinger in a normal way (Big to big adding the 2 links); a subsequent tweak to the stinger position will increase the chain route adding tension. Fine lines may but it may help.
Anyway the part about the bolt still holds true as it will stop the chain getting between the ring and the stay.

crimsondynamo

@robst3

Did you ever get a solution?

The Rookie

BlueAdvocate wrote:

Does it not? really? I would suggest that's how its fitted. Yes you can measure the chain over the stinger in a normal way (Big to big adding the 2 links); a subsequent tweak to the stinger position will increase the chain route adding tension.

Nope still adds no tension, there is no spring in it, it just changes the static chain route, the tension is purely a function of the position of the rear mech and the spring tension that creates, as the chain is sized to the same effective length with and without the stinger the tension has not changed at all, yes if you subsequantly move the stinger a fraction so you shorten the chain length by a tiny bit but still within the guide for sizing, you will chainge tension by a tiny bit, but relevant, no.

BlueAdvocate

The Beginner wrote:

BlueAdvocate wrote:

Does it not? really? I would suggest that's how its fitted. Yes you can measure the chain over the stinger in a normal way (Big to big adding the 2 links); a subsequent tweak to the stinger position will increase the chain route adding tension.

Nope still adds no tension, ..... if you subsequently move the stinger a fraction so you shorten the chain length by a tiny bit but still within the guide for sizing, you will change tension by a tiny bit, but relevant, no.

Yes the spring in the mech is pulled back as the chain route is changed which applies more force and hence adds more tension.
My point is the your original statement is that it adds no tension "AT ALL" is wrong and you admit it above. Perhaps your original reply should have been on the that it doesn't enough tension to make a difference; that may be true (I did say fine lines).
I was trying to be helpful but you thought you would get all shouty and dismissive.
Back to the bolt here's the thread where Northwind mentioned the bolt through the stinger
http://www.bikeradar.com/forums/viewtopic.php?f=20005&t=12778752&p=16962450&hilit=stinger#p16962450
It may not work, it may.

robst3

Sorry for the late reply...

I have shortened the chain by 1 link (i.e. it is now 1 link shorter than the Shimano tech docs suggest it should be) and it seems to have improved the situation. I've ridden twice since, about 3 hours riding each time and have only had the chain suck twice. I am being extra careful with my shifting though.

Anyone who says the frame has nothing to do with the problem is talking crap. There is obviously less chainstay clearance on the 456c and so even a small amount of chain suck will cause the drivetrain to jam completely. It might not directly cause chain suck but given a small amount of (seemingly inevitable given the amount of different drive trains people have experienced this with) chain suck it causes a big problem...

I may shorten my chain another link and see if it improves things further.

Chunkers1980

The frame does have nothing to do with it. Chainsuck causes the jamming, with jamming exasibated by the frame clearance.

Removing chain links is a bad idea. If your mech has a Constant Spring rate through its arc then it won't make any difference ignoring the angles.

The Rookie

BlueAdvocate wrote:

My point is the your original statement is that it adds no tension "AT ALL" is wrong and you admit it above.

Depends on whether you can do it or not, materially it has no effect.

robst3

Chunkers1980 wrote:

The frame does have nothing to do with it. Chainsuck causes the jamming, with jamming exasibated by the frame clearance.

Removing chain links is a bad idea. If your mech has a Constant Spring rate through its arc then it won't make any difference ignoring the angles.

It wouldn't jam if there was more clearance... so the frame does cause it.

Removing a link has improved things 100%. If you have a better solution to the problem why not post it instead of splitting hairs

Chunkers1980

No it would not jam, but you'd still have chainsuck.

It's not splitting hairs, you are just making sweeping statements.

cobba

Chain Suck: the COMPLETE story