In case anybody wants to try this or is wondering if it works: I have installed my 1992 Koga Miyata Exerciser 7speed steel bike on my Wahoo Kickr Core. Of course spacers are needed to fit a 7speed cassette on the Kickr. It was running great, but the jumps between the 7 sprokets were a bit to big for me (if you're an exact cadence guy...). So I switched to an 11speed cassette and chain......and....surprise: it works!!

I'm using:

-Steel frame (126mm original spacing fits on the Kickr with a bit of force)

-Shimano 1055 rear derailleur (short)

-Shimano 1055 crankset (52/39)

-Shimano 7speed downtube shifters (for 11speed you have to switch to "friction mode" because the indexing is 7speed...)

-Shimano 105 11speed 11-28 cassette

-Shimano 105 chain (11speed)