Originally Posted by
LongVehicle
The 6770 series is the electronic, so the Campy shifter isn't an option for me. One of the "company selling points" was that the front derailleur is supposed to perform shifts while under significant pedal force...Single bike users rave over the ability to shift the front while climbing without reducing pedal force. Either way, we've tried this with no success (when the problem is occurring). I don't know if a longer chain would work. It seems that, with all else but chain length being equal, "x" amount of force on the pedals would give "x" tension on the chain between the cog and the rings. Changing the chainline isn't an option for me, but angling the front cage may be. I am running a home-made chain catcher, but the programming/design of the front derailure is supposed to "over-shift" just a bit and then return to proper alignment to better facilitate shifts. It also self-adjusts in relation to the RD position (odd to hear the first few times, but amusing to watch in the repair stand). The double shift works every time as long as my pilot remembers to do it (most of my pilots have at some point double shifted a mechanical setup and dropped the chain...it's a hard habit for them to develop I guess).
Thanks, there are some ideas to try.
Sorry for my mistake. I assumed you had mechanical - well you how assuming goes. You are right Di2's big selling point is front shift perfection. With all the power the electric FD is supposed to have what happens when you have a failed front shift? I guess it just stays in the big ring while rubbing the FD cage a lot making lots and lots of noise?
Just guessing here hopefully someone with more knowledge will chime in:
When in the big ring and small cog is there any extra room between the outside of the chain and the FD cage? If so maybe an adjustment can be made to have less gap there so that when the FD moves the same distance to the inside it ends up further inboard when shifted into the small ring.