Originally Posted by
wgscott
This worked in my case. I wanted to keep my current (Di2 Ultegra) front derailleur, because with Di2, I would be forced to replace both front and rear, which would have been cost-prohibitive.
The other thing is I have a clamp-on front derailleur, which might give more options for adjustment compared to a braze-on mount. I did have to crank the H-limit screw almost all the way for it to work.
I think the main issue would have been with 5800/6800/9000 mechanical long arm FDs with the limits pushed out. Depending on the clearance between the seattube and FD mount and the rear tire the arm could hit the tire. Since you are running Di2 that likely isn't going to be an issue but shimano is pretty conservative in general with these compatibility recs