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105 Rear Mech Jumpy...
 

[Closed] 105 Rear Mech Jumpyness

Posts: 1760
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[#8167686]

Sure I've seen this on here before, I've posted at least once but it was not long after the group was launched (105/5800)

Every 12 months or so the bottom of the cage starts bouncing up and down with the chain miss-aligning on the gear, last weekend it involved the rear mech bouncing up and ripping itself off (through peddling force I admit....) and bending the rear hanger.

Checked all the usual, hanger straight, chain length, chain direction, indexing, everything you'd usually go through.

Is it a known fault?

Tempted to go Ultegra chain/cassette/RM this time around


 
Posted : 18/11/2016 8:47 pm
Posts: 77
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Interesting as I had the same problem on my last frame....every so often the rear mech would jump up and down like a banshee when in the larger cogs. Never got the bottom of it as it happened quite infrequently. Since then I have swapped frames and cables and the problem seems to have gone but I wont rule it coming back as I havent ridden the new frame much. I wonder whether its related to chain alignment?


 
Posted : 18/11/2016 9:05 pm
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Sounds like a stiff link.


 
Posted : 18/11/2016 9:08 pm
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That's exactly how it behaves SR, I'm using a Shimano 105 chain installed by the pin (I very rarely find these stiff link if joined correctly) and checked after.


 
Posted : 18/11/2016 9:24 pm
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Correct ratio RM's been fitted as well


 
Posted : 18/11/2016 9:24 pm