Chainsuck problem

[Dare]

Hej guys!

I have encountered horrible case of chainsuck which ruined paint behind the cransks (I almost started crying!!). I don't know what could have caused it as I don't see that chainrings are wornedout. In any case, it happens only when shifting from small chainring to middle one. Do you guys have any advice for it? New chainrings or chainsuck protection device? Could it be something with front derailleur (as it started happening after I fine adjusted FD).

In case I need to buy new chainrings can somebody suggest the place to get them from? It is for middleburn crankset I have attached picture (does anyone know BCDs of needed chainrings?)

 

[k-rod]

Nothing worse than just finishing a lovingly attended pristine build, and then hearing that sound when the chain gets jammed up between the chain-stay and the sprockets .... and you just 'know' that some of that lovely new paint was defaced and that there might even be bare metal now exposed.

'Tiz a horrible sound.

 

[hamster]

Worn chain? I seemed to get it worse with Shimano chains. As you say the rings look OK.

You need 94pcd chain rings. RJC Extreme still do Middleburn ones, otherwise try Spa Cycles for Stronglight or TA.

But try swapping the chain first.

 

[Dare]

Nothing worse than just finishing a lovingly attended pristine build, and then hearing that sound when the chain gets jammed up between the chain-stay and the sprockets .... and you just 'know' that some of that lovely new paint was defaced and that there might even be bare metal now exposed.

'Tiz a horrible sound.

Indeed!!!

Worn chain? I seemed to get it worse with Shimano chains. As you say the rings look OK.

You need 94pcd chain rings. RJC Extreme still do Middleburn ones, otherwise try Spa Cycles for Stronglight or TA.

But try swapping the chain first.

The chain is brand new.

 

[integerspin]

So is the chain sucked by the granny?
I have only ever had it happen on downshifts
from top or middle. And it happens to me with new chain
on worn rings, I remember to take it easy on down shifts
for a while after it's happened and then it's OK.

 

[Dare]

Yes, that is the weird part, as it usually is like you say; when you down shift. For me it was when you up shift from granny to middle ring and chain doesn't get off the granny ring.

 

[k-rod]

This may sound silly, but perhaps you're not pushing the shifter lever all the way through it's shifting motion on your up-shift, thus causing the chain to 'not quite' get taken up onto the middle ring, to then fall back onto the granny ring (and worse - past it and in between it and the frame)?

 

[bj]

Re:

Could the chain be jamming a bit against the adjacent bigger chainring?

Just a few thoughts if so:

1) Thin enough chain?
2) Chain ring spacing wide enough? ie no shims missing between the chainrings.
3) Pround or sticky chain pin?

 

[jimo746]

You said it was a new chain? Should be ok as they come with "lube" on them. I take it the chain I'd suitable for the number of gears you're using? 7/8 speed?

Got a spare decent condition chainring you could try?

The chainring bolts don't stick out a bit on the inside of the middle ring at all?

Edit: just noticed chain is brand new, middle chainring is worn/used. That could be your problem.

 

[tonedeaf101]

Do the rings have ramps?
I used to have all sorts of issues with older Shimano rings causing chainsuck, so much so I threw my bike into the bracken once in a right paddy fit.
Teeth may be ok, but ramps might be catching the chain possibly.