I have an 90’s Shimano FD-M301 top pull front derailleur on my steel touring bike. I’m using bar end shifters. The crankset I want to use is an older Tiagra triple with the big ring removed making it a wide/low crankset. (42/30). These are the cranks: https://bankruptbikeparts.co.uk/products/shimano-tiagra-175mm-road-bike-9-speed-triple-52-42-30-teeth-chainset-fc-4403
The problems I’m having is that firstly the derailleur won’t go wide enough to move the chain to the big ring on the outside of the cranks. I’ve adjusted the limit screws and it still won’t go far enough. Secondly the derailleur hits the chainstay when it’s on the smaller ring. It’s a band on derailleur, so I have quite a bit of adjustment.
Here’s the derailleur (not my photo) and the manual. https://si.shimano.com/en/pdfs/si/U-016A/SI-U-016A-000-00-ENG.pdf
by Which_Bar_9457
3 Comments
M301 is mtb and tiagra is road. They have different cable pull ratio and are not compatible and they move a bit other on 3speed.
And theres a different between 2 and 3 speed too
What is your chain line? Older front derailleurs used and bikes used a ≈43mm chain line. Modern bikes use a ≈45mm chain line. It is possible your chain line is exceeding ≈45mm.
Also different square taper cranksets use different spindle lengths for the BB. You probably need to get a new BB with a shorter spindle.
If you are removing the 52T outermost ring, why are you trying to have the derailleur shift to that 52 “big ring?” Or do you mean that the derailleur won’t even shift to the 42T ring?
Also, are you certain you have the correct bottom bracket spindle length for that crankset? If it’s too long, it’ll of course push the chainrings further outboard.
>Secondly the derailleur hits the chainstay when it’s on the smaller ring.
Then mount it higher. It was designed to clear the largest of 3 chainrings, which is no longer there.