Originally Posted by
Andrew R Stewart
But a question. I don't think I've seen AL stops on a steel frame, certainly not on a "vintage" frame (whatever vintage means anymore). Are you sure they're AL? Andy.
I believe the OP is refering to the Shimano (or other) adapters which are attached to a braze-on downtube shifter boss. I've seen these get frozen on over time, and if I can't pop them off, I slot them with a saw or Dremel, then insert a screwdriver and twist to spread them slightly.