@Ricky_John: Did you watch the video and follow the instructions? Using a seven speed cassette with the additional, required spacer, requires a little mechanical work with a file to get the cassette to line up with the hub.
Yeah followed that. In fact I found a 4mm spacer online that was made due 7 speed cassette and came with the rivet gaps already in place.
The only thing I can think of is that either the spacing between the cogs on the freehub cassette that is on the trainer is slightly different from the freewheel cassette on he bike, or, the teeth difference 12-28T vs 14-28T is more of an issue than I thought it might be
I suspect spacing is not the problem. According to Sheldon Brown’s site, Shimano 7 speed cassettes and 7 speed freewheels both have 5 mm spacing:
I disagree somewhat. Yes, steel frames can crack when you widen the dropouts. However you can successfully cold set them, which is what I did on a 1980 Windsor Pro. I expanded the dropouts from 126-130 mm, as you mentioned, and have now ridden the bike for two years with an 11-speed cassette. And I can use that bike on a smart trainer. So, there are other options for SteveK.
Sram gx eagle 12 speed with spacer, works like a charm.
No clearance issues.
This is on the standard hub, not the XDR type.
yeah came here to say this, I bought the XDR/XD freehub but forgot the SRAM NX Eagle cassette fits on Shimano. I already had the cassette from the original wheelset that came with my mountain bike. It fit on the trainer freehub just fine and shifts smoothly.