10 speed cassette for 11 & 9 speed bikes on kickr core


I just picked up a new kickr core (woo) and I realized that I have a spare 10speed cassette lying around. Both my wife and I want to use the trainer but my bike is an 11 speed and hers is a 9 speed. Will we be able to use both bikes on the same trainer with the 10speed cassette?

I did call wahoo support and they mentioned it should work but the nice person on the line didn’t sound particularly confident so I decided this forum might be a place where people have tried/asked/know about this kinda thing before.


I think you can, I’m sure you can find the one perfect gear for each bike and just use erg mode. Of course shifting with both would be wonky but I think that should work (I’ve never tried it myself but believe this to be the case)


The issue is the shifters. Shimano 9-speed pulls 2.5mm of cable per click, 10-speed 2.3mm, 11-speed 2.7. Derailleur movement per mm of cable pull is the same for 9 and 10, but different on 11. And gear spacing is different on all 3. So - you won’t be able to shift correctly with a 9-speed bike (meaning a 9-speed shifter) on a 10-speed cassette, nor with an 11-speed bike on a 10-speed cassette. The 11-speed chain may not like the 10-speed cassette either (it’s narrower than a 10-speed chain)

What you can do however, is pick a gear on the cassette, shift close enough to it, and adjust with the cable barrel adjust onto it. You will be limited to that gear on either of the chainrings.

And run it in erg mode, of course, as @hubcyclist indicated.

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For the OCD, this is probably the best resource for this stuff (assuming you are mechanically-enclined):

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