First, it's not my first go around with front derailleurs. That said, I have a 105 groupset on a Specialized Diverge. It was 1x for a while, but wanted to get it more "road" ready and put the original 105 front mech on it again, swapping the chainrings, etc. The rear mech is fine. Everything is pretty new, the cables/housings are new. The teeth on the front and rear are all straight and good.
But through all the adjustments (yes, even followed this guy) I just cannot get that thing to work right, though it did before I took it off. No matter how much tension I get on it, it's doing everything except one thing right. I get low limit perfect, tension the cable, cannot get it to shift to the larger, adjust everything, can just barely get it on, then it won't shift into the lower (the outer link of the chain "sits" on the ring – wth?). Take it all apart, adjustment, retighten, go through the process, now I have chain rub I can't get rid of. Do it again, something else.
It's driving me mad and I'm at the point of going back to 1x on this thing. Any suggestions? It's your standard 11 speed, 52/34 front, 11-34 rear. All 105.
by ando_da_pando
3 Comments
Should be straight forward honestly:
1. Set height and alignment. Should be 1-2mm above the largest cog when cable is loose. Outside of cage should be parallel with largest cog. Im guessing this is your issue here if its all the same parts and was working before. I’ve found shifting to be very sensitive to this step and use a caliper to make sure things are parallel.
2. Set low limit. 1mm of clearance with rear in biggest, front in smallest
3. Set cable tension.
4. Set high limit. 1mm clearance with rear in smallest, front in biggest. I have to go to maybe 2-3mm to get mine to shift correctly.
5. Play with cable tension on the barrel adjusters for fine tuning.
Thats about it. If youre still having issues, there must be something bent or broken. Maybe you put a chainring on backwards and the chain lines are messed up? All this stuff was working togther before right? My bike shop said something about Shimano changing pull rations on the newer stuff. So if you have new shifters, that could be it. This was in the context of a 3×9 from 2006, so it may not apply to your gear.
I watched the video you linked. The guy is not demonstrating a good process and what he’s instructing you to do is a weird hybrid of the traditional lever-arm front derailleur adjustment process and the newer Toggle-type front derailleur adjustment process. The two are different enough that realistically, they cannot both be demonstrated in the same video on the same derailleur. His process will *not* accurately or consistently give proper indexing for the Toggle-type front derailleur, and it’s more of a fluke than anything that he managed to do so on the bike he was demonstrating.
You should use the official Shimano documents and follow the Shimano process *to the letter*.
https://si.shimano.com/en/pdfs/dm/RAFD001/DM-RAFD001-05-ENG.pdf
Start all the way back from “Installation”. Read each step carefully, do not skip any steps, and do not perform any extraneous steps either.
If you follow the Shimano process properly, you should be able to end up with a working derailleur.
EDIT: I realized I made an assumption. Do you have FD-R7000 or FD-5800?
If you have R7000, the document I linked is correct. If you have FD-5800, you’d need to find the dealer manual for that instead. (5800 is not a Toggle-type front derailleur).
First make sure that your upper limit is far enough out when you go to do the adjustment. If that fails you run into an engineering problem that bike companies seem to just assume.
Generally it is not possible to put enough tension on a front derailleur from the pinch bolt.
There are in line cable adjusters that I use to add tension after the pinch bolt has been secured. This usually adds more tension than you can yanking on the cable. And give much more ability to fine tune for your riding style.