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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!!
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.
the middle chainring positon is controlled not y the limit stops but the cable tension so adjust the cable stop until it overshifts then slacken the cable tension till it no longer does
Dropping the mech down the tube can help as well
In my limited experience...mtb mechs designed for triple systems...don't work so well on double systems especially if the chain rings on the double have a different amount of teeth than the original intended use was for.
Mine works fine
typed too slow
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!
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 🙂
Patience isn't a strong point, I've been at for a good couple of hours over the last two nights, but I'll have another go tomorrow night.
LBS is a non starter, I don't have much faith in any of my local ones unfortunately 🙁
Are you using a workstand?
No I don't use a bash ring. Yo will have to adjust the cable tension to get the mech to sit in the right place. The trail an error if nothing else. wind the upper stop out until it will overshift then use the cable tension to get the mech position right
I am using a workstand (one of the best things I've ever bought).
Thanks TJ, should definately work then, I highly suspect my lack of mechanical skills are the down fall, I'll give it another go tonight.
[url= http://techdocs.shimano.com/media/techdocs/content/cycle/SI/SLX/SI_5KV0A/SI-5KV0A-003-ENG_v1_m56577569830765729.PDF ]This might help.[/url]
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.
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 😀