It's the cylindrical part. It's an oval, but seems to be too 'long' to fit inside the circular hole of shifter or mounting ring. On both sides. I am a bit baffled - I've owned over 80 vintage bikes and have never seen this.which bit is too big? is it the square bit for the plate or the cylindrical part?
Yes - they won't fit. The 'lozenge' shaped piece seems too long to go through the middle.I'm having a think, I guess you have something like this to fit over the boss?
https://www.treefortbikes.com/Shimano-7800-Braze-On-Shift-Lever-Boss-Cover-Radiused
Looking online there are a few example pictures out there all showing Speeders with El Cheapo Shimano shifters. So perhaps it is then the case that a budget pair may have a wider diameter recess to fit your bosses.I have this late 80s (?) Giant Speeder and I can’t fit any D/T shifter onto the bosses? I’ve tried Shimano and Suntour and none of them fit.
Am I missing something - was there more than one size?