Wahoo Kickr cassette question I just bought the Wahoo Kickr, but I have a compatibility question. I have a Trek Madone 4.7 fitted with a Shimano 105 11-28, 10 speed cassette. Just when I think I understand whether I can make this work, I get myself confused again. Will the Kickr cassette work with my existing drivetrain?
If it won’t work, I was going to buy a 10-speed cassette to put on the Kickr, but instead, I’m thinking of upgrading my bike to an 11-speed cassette (plus shifter, chain, etc.). My husband’s bike is an 11-speed, so I was thinking it would be better to keep the cassette the Kickr comes with.
Is there a way to make the 11-speed cassette work with my 10-speed setup? Sorry if my question is confusing!
You're right - something has to change.  11 will not work properly with 10, and vise versa.
Ideally, you're going to have to standarise on 11 speed on both bikes.  That means new shifter, chain, cassette, and maybe rear derailleur.  This is probably the most expensive solution, though you can sell off the 10 speed parts to recoup some funds.
Your other option is to move your 10 speed cassette to the trainer for your bike, (or have a second 10 speed cassette spare)  and swap an 11 speed cassette onto trainer for the other bike.  THis is faddly and will add wear and inconvenience.
Your third option is to find a third bike and leave it on the trainer permanently to share, though that bike is unlikely to fit both of you.   Or buy a second trainer and configure for 10 speed (though this is a ludicrously expensive solution)