In short, no. But you could fit a spacer and use your 10 speed cassette

The answer is maybe, depending on how you use your trainer. If you’re using erg mode on the trainer, you can typically find a gear that operates smoothly. Leave it in that gear for your erg mode workout (you don’t change gears when doing an erg mode workout). Related tip is to put your front chain ring on the small ring, which helps to reduce noise from the trainer and, IMO, feels more natural in erg mode.

If you want to switch gears on the trainer, like riding Zwift (not in erg mode), then no, you cannot use your 10 speed bike with the 11 speed cassette on the trainer.

+1. I live with this situation because my sig other has 11 and I have 10. I mostly leave the 11 on and ride erg mode, since she prefers to ride courses, but it's only takes a minute to switch in a 10.

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Thanks for the feedback all.

I’ll just suck it up and switch cassettes when I need to. And it’s my tri bike that’s the 11 speed which I’m done for the year on that. I can just switch over after the new year when I need to start getting back on the tri bike.