Originally Posted by
elston1999
not a modern front derailleur. Old suntour.
How old, i.e. which model FD?
Generally it was during the mid-90's that shaping of the front derailer's inner cage plate for specific middle-big chainring count differences took over, but such shaping did develop, to some degree, years earlier.
I've been brought several bikes where a well-intended shop mechanic's chainring size changes rendered a customer's triple-drivetrain practically unusable, even after the customer had brought it back to get it's shifting problems corrected!