I recently removed my outer chainring and wound the front mech limit adjuster in so that I couldn’t forget and drop the chain. That’s was 100%, so when the mech died I replaced with an SLX double specific and now at least once a ride it ‘over shifts’ the middle ring and the chain drops off over the crank arm. Ok so the limit adjuster needs adjusting, except that even a small tweak makes it very hard to push the shifter enough to make the index click in to place. Would a double SLX shifter help or keep looking elsewhere for the issue? Think I’ll replace the inner and outer cables next.

TIA

Have you got the cable routing at the mech right on the new one? I had a similar problem with overshifting, but it was because I had clamped the cable incorrectly.

Double and triple shifts move the mech different amounts as the chainrings have different spacing. If you just remove the outer ring from a triple that’s fine, there a “ghost” shift there but if you’ve got a specific double ring, the mech is still trying to shift across a triple gap hence the overshift.

New shifter time.

Double and triple shifts move the mech different amounts as the chainrings have different spacing. If you just remove the outer ring from a triple that’s fine, there a “ghost” shift there but if you’ve got a specific double ring, the mech is still trying to shift across a triple gap hence the overshift.

New shifter time.

Nope. The Chainrings still have the same spacing. The Slx double works with triple shifters fine. It pulls the same amount of cable as the triple per shift. I have an xt triple shifter on an slx double that works fine.

just like balfa said – not new shifter time. Me, and plenty of my friends are running double setups, on double ring setups, with double and triple specific cranks with triple shifters just fine.

Just check the cablke clamp position, don’t adjust your front mech too low when you remove your big chainring (this matters as the cage is profiled) and persevere with setup.

Wrong mech height is the most common cause of mis-shifting in my experience.

Hope this saves the cost of a new shifter!

Rob
bigrobracing.co.uk

🙄
🙁

Good grief CrazyLegs – never have I seen so much absolute crap about so little.

People posting such rubbish says it all about trying to make technical enquiries on internet forums.

Fortunately Balfa & rob have stepped in to save the OP with the correct information ! 🙂

(As for even thinking that a double specific shifter exists, good luck with that one !)

Slacken the cable tension until it shifts easily onto the “middle” ring with the limit stop where it needs to be to stop overshifting. Then adjust the lower limit to stop it dropping off the inner ring.

It’s OK to limit the travel at the bottom of the range short of where the shifter puts it, because you just end up with a slack cable, but if you limit travel at the top of the range short of where the shifter wants to put it you end up with an over-tight cable and the problem you describe, so you need to slacken the cable a bit.

Ah! Too much cable tension, that’s exactly it! Thanks to everyone and especially pdw. It’s scary what sleep deprevation does to me. Time to head to the man cave for a fettle.

My (albeit much used) SLX double mech doesnt like shifting down to the granny, I think the springs maybe weaker or something. Sometimes doesnt move over even with all the cable slackened off after shifter chages.

(As for even thinking that a double specific shifter exists, good luck with that one !)

I’m probably making a tit of myself by showing my ignorance, but here goes … I know the OP is Shimano related but, is a SRAM XX front shifter not double specific.
Come to think of it, don’t they do XTR double specific now (at least switchable between triple & double).

..poem – you’re right, I was referring to Shimano as the OP stated SLX.

And yes I think the XTR and certainly the 2012 XT is switchable between the 2 as they have spaced the double cranksets differently, but it is switchable and not double specific.