- Best Cure for Overshifting
So I’m having a nightmare trying to set the front mech up now I’ve removed the outer chainring and replaced the middle with a Blackspire super pro 34t on my 10s SLX chainset. It doesn’t seem to matter where I set the limit screw it either overshifts the middle ring or won’t shift from inner to middle. So I’m after either advice on how to get it working or the best thing to do to stop it, ie. stick a bash on.
Please help, this is driving me insane!!Posted 6 years agoConan257Member
Front mech’s are always a pain in the ass.
The easiest method I found is, assuming your mech is straight and at the correct height:
Set screw for smallest chainring, attach cable ensuring it is nice and tight, use shifter to move up to top ring and adjust screw to the point where the chain doesn’t fall off the top.
Readjust the bottom screw if required.
If your chain stays on the bottom ring and top ring when they’re selected by the shifter, but doesn’t stay on the middle ring. Then I’d say you’ve either got a mech problem or a shifter problem.Posted 6 years ago
Thanks for all the suggestions, I’ll have a go at dropping the mech tomorrow. TBH I’m starting to lose hope so I’m going to order a bash, which I can always send back if I get it working! Prob a 32/34t one of these: http://www.chainreactioncycles.com/Models.aspx?ModelID=19042
TJ, do you use a bash ring?
BTW, I’m all 9s bar the chainset and front mech, which has so far been working fine!Posted 6 years ago
keep at it, they can be little bastards to set up sometimes, no matter how methodical you’re being. It’ll just start working and you’ll have no idea what you did right.
cheaper than a bash ring though is swallowing your pride and getting your LBS to set it up 🙂Posted 6 years agoPJM1974Member
As has already been said, patience usually pays dividends. Front mechs are a complete and utter bugger to set up. Small adjustments to the position of the mech on the frame may help, you can drop the mech slightly as you won’t have to cater for the big ring and it’s worth checking the alignment isn’t out, that would provoke the issue.
You can get double speed specific mechs these days from SLX upwards which may mitigate the problem. I gave up with fiddling with screws and just learned not to shift more than once either way. Yes, there were a lot of sweary moments and a couple of dropped chains.Posted 6 years ago
Just want to say a big thank you to everyone. Finally got it shifting up and down pretty well, though it took another hour in the garage! I’ve dropped the mech about 5mm from its original position, it was possibly slightly high in the first place and twisted it slightly! Fingers crossed it behaves it’s self out on the trail 😀Posted 6 years ago
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