View Full Version : Chain Jam
Hardster
06-18-2012, 05:15 AM
So I've been happily riding my Responsorium that I built up with 11 speed Chorus for a while now. Over the last months down-shifting from the large (50 tooth) ring to the 34 when it was on and now the 36 tooth that I replaced it with, causes the chain to jam sometimes for a moment until I back-pedal just a short amount before pushing forward again. When I inspected the frame it seemed that the chain was jamming between the big ring and the outer side of the chain stay. The paint has been scored away.
Is this a front derailleur 'toe-in' adjustment or something else?
Thanks in advance.
merlincustom1
06-18-2012, 07:16 AM
I'm having a hard time picturing the intersection of the big ring and the outer side of the chain stay?
AgilisMerlin
06-18-2012, 07:27 AM
check the chainring(s) teeth for burs.
if found, file
check chain length (for slop) when shifting
where suck/wrap is occuring - wrap stay, in old innertube or electrical tape, till figure out problem.
just thinking of frame, yo
oldpotatoe
06-18-2012, 07:33 AM
So I've been happily riding my Responsorium that I built up with 11 speed Chorus for a while now. Over the last months down-shifting from the large (50 tooth) ring to the 34 when it was on and now the 36 tooth that I replaced it with, causes the chain to jam sometimes for a moment until I back-pedal just a short amount before pushing forward again. When I inspected the frame it seemed that the chain was jamming between the big ring and the outer side of the chain stay. The paint has been scored away.
Is this a front derailleur 'toe-in' adjustment or something else?
Thanks in advance.
Chain suck. Big ring may be worn out. Sharkfinned, that tends to hold onto the chain after shifting that drags it between the rings and frame.
Fairly quick wear on the big ring pretty common on Compcts also. Big ring used a lot, lotsa cross chaining as well.
AgilisMerlin
06-18-2012, 07:39 AM
like when the teeth look like cresting waves :banana: = the big :no:
as stated above ^
Bob Loblaw
06-18-2012, 07:47 AM
+1 for worn ring(s) or worn chain or both.
Less likely but also possible, could also be the chain is too long.
BL
Hardster
06-18-2012, 07:55 AM
This grouppo is still relatively new. Only a few thousand kilometers. I'll check the chainlength as well. Cheers
fourflys
06-18-2012, 10:15 AM
take a second and make sure the rings are put on correctly... by that I mean the correct side facing out... it's easier than you think to face the inner ring wrong way... ;)
Black Dog
06-18-2012, 01:27 PM
I bet it is the length of the chain. I have the same set up as you do. I keep my chain on the long side so I can switch between the 12-15 (normal riding) and 12-29 (for the mountains) without having to muck around with chain length. I get the suck doing the same thing. With a shorter chain: no suck. When I am in the 34-12 the chain just rubs on the bottom of the pulley cage on the RD. If you are not dropping to the small ring and shifting to a smaller cog simultaneously while under load you should be able to avoid the suck.
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