For close to a year I've been adjusting and readjusting my GRX front derailleur, following Shimano and every other guide I can find, without being able to eliminate rub at the extreme ends of the gear range. I've found an annoyingly simple cause; a cheap and nasty band adapter.
I've attached pics that hopefully illustrate the offset between the genuine shimano part (still only cost a tenner) and the horrible part my bike was sold fitted with. As this particular FD design seems especially sensitive to limit screw adjustment, it simply couldn't handle being sat inboard by an extra 2/3mm.
I'm sure there are other ways around this issue but hopefully this is helpful to someone else banging their head against the same wall.
by Ok-Mail-5918
5 Comments
Use a 2mm Allen key to tighten the screw that protrudes above the front derailleur cage.
I have a GRX 2×12 equipped bike and I had derailleur rub when I first bought my bike even when using the trim positions. I adjusted it to a point where I feel it provides the minimum rub at the lowest and highest gears when using the trim positions. I find I have to be more careful about FD position to ensure my derailleur doesn’t rub than my previous 2×9 bike but with the trim positions I can access almost the entire range of my cassette without any issues. It’s pretty fiddly for sure.
I’ve been using this one from Origin8 on my Midnight Special with a GRX front derailleur and crankset for about a year now. It’s perfect and pretty
https://ebay.us/m/72C95m
Ahhh that’s annoying. I bought the Shimano band adapter for my GRX derailleur but had to go with the aftermarket one because my frame is so small that one of the rack mounts is exactly the spot where the band would sit. Had to go with one of those ones with vertical adjustment. Haven’t had any issues so far but will be frustrating if it does happen.
These specific derailleurs have a detailed and specific setup procedure that’s just a bit different. Look up the Shimano manual and follow the steps exactly.