Originally Posted by
rlpfromak
I’ve got old bike with a Eisentraut A frame and a variety of Campy, Dura Ace, and Crane components. I bought it in 1976 and recently overhauled it, as it had sat unridden for many years. I kept most of the original components, including a Shimano Crane rear derailleur (the pedals are Campy and the crank is Dura Ace). I’d like to use it with a direct drive smart trainer, something like a Tacx Flux S, but I’m worried that the derailleur won’t work for the larger cassettes now present on bikes (you have to buy a cassette for the Flux S). The largest gear on my current freewheel (not a cassette) has only 26 teeth. Does anybody know how large a cassette this derailleur will support?
28t.
But before you go ordering a cassette, that's not the only problem here: you'd need to buy a new chain and install new chainrings at the very least to use to use that trainer's stock cassette since it's 11sp. The cheapest and much easier solution would be to install an 8-sp cassette with a 25-28t large gear and spacer on that trainer, that way you can leave the rest of your bike alone.