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So we have a 2012 XT mech that’s been sitting a while but otherwise appears to be fully working. Up front is 2 x chainset. Bike is a hard tail.
When in the big ring at the front, the mech goes up the cassette ok but does not drop down the range at all, instead leaving a loop of slack cable across the top tube. When in the smaller ring up front, there are no issues.
The bike has been recently re-cabled with new outers also and has no sharp kinks out I don’t think its a sticky cable, especially considering it only happens in the big ring.
Any ideas gratefully received…
Had similar on a 12sp mech recently, needed a new mech.
You could try lubing the spring in the mech and see if it helps
Could need a clean- 12 speed shimano seems particularly prone to it but they all benefit from a strip down of the main pivot and some fresh grease from time to time.
It’s the plate axle (ie the absolute hardest part to get to) that needs the grease on the 12s stuff
Thanks for advice I’ll give those a go. It is btw 10 speed….
Aye, the basic mechanics are pretty similar though- I haven’t done a 10s for a while but can’t remember anything massively different. More just noting that 12s stuff seems particularly prone to it
Tried just adding a bit of b-tension to help the chain step off the biggest sprocket?
Sticky pivot needs a grease.
If its only on the big ring, I'm going to suggest that silly Oldman isn't actually so silly and the top jockeywheel is too close to the sprockets.
I’m going to suggest that silly Oldman isn’t actually so silly and the top jockeywheel is too close to the sprockets.
It turns out that was correct, thanks for the advice. The B tension screw is pretty much all the way in now so I guess the spring has lots a bit of strength over time and eventually the mech will need replacing, but for now it all works fine again.
👍
FWIW I always leave bikes in the smallest rear cog to take the tension out the spring when they’re in the house unused.
A habit from old sram mechs which would go baggy in a year otherwise but I’m convinced it’s helpful for all mechs…