Hi – recently started bike commuting, new bike with shimano di2 105 group set. Since the start I’ve had an issue with chain rub on the FD – gone through all the adjustment settings several times and tweaked it++ without luck. At the moment it’s only an issue in the very high gears 50×11-15 step range (details below). It seems as though the FD is just too narrow and can only accommodate 2-3 / 5 rear gears in this range. At the moment it rubs at the 50×11 (outside – black plastic) and 50×15 (inside – metal). FD doesn’t look bent or physically damaged at all. Any idea of the cause or how to fix this? Hopefully im just missing something obvious.. and this isn’t a 105 di2 issue?
I don’t need the full range of gears and only use 50×11-24, 34×14-34. So cross chain extremes aren’t an issue, just have a decent flat stretch on my commute so would be nice to have the full range of high gears available. Perhaps there is a way to make the trim adjust earlier?
50 x 11 : [photo 1] rubs on black plastic lateral side of derailleur
50 x 12 : no rub (or slight rub)
50 x 13-14 : no rub
50 x 15 : [photo 2] rubs on the inside metal
(trim adjusts)
50 x 17/19/21 : no rub
(trim adjusts)
50 x 24 : no rub
(And no issues beyond this with any lower gears, including throughout the 34 x range).
[photo 3 is side view in case there is a positioning issue but it looks ok to me]
Bike was an online purchase (from reputable seller) but hoping to try and wait until 6 weeks so the bike / chain / brakes / etc. settled before getting a proper service from my LBS.
by MattAus03