Nemosengineer that's pretty special. Let us see it as it progresses.
Today I had a big success with our tandem. Last year, I changed the rear hub, rear derailleur, cassette, chain, and shifter. I left the front derailleur and shifter as they were. The drivetrain was originally 3x7, and the change was to 11-speed in the rear. The shifter and derailleur are absolutely outstanding, but the 11-speed chain did not work well with the 7-speed crankset. Whenever I shifted down from the big chainring, the chain fell between the big and middle chainrings. It almost threw us off the bike every time. My spouse told me not to shift it while we rode it until I've fixed it. I got advice in the Mechanics section, and it sounded like the best bet was to use a more modern crankset.
So I went from this Shimano crankset to this Campagnolo 10-speed. And the whole swap was fairly easy.
I had changed the big chainring recently. Originally it was 28/38/48, and I replaced the 48 with a 54. That didn't make the shifting better or worse.
