Getting Kickr Core Trainer to work with 7-speed cassette?
 

The Kickr Core trainer looks like it will work with my wife's bike as far as the quick-release dimensions go, but it says it works with 8, 9, 10, and 11 speed cassettes, and her cassette is a 7-speed (SunRace MFM300 freewheel, 14-34, 7 speed).

Does this mean the Kicker Core is a no-go entirely, or would I just need to buy additional parts for the bike, the trainer, or both? I have no experience with trainers, so bear with me if this is a dumb question.

The Kickr Core comes with an 11 speed freehub and an additional spacer to allow the use of 8-10 speed cassettes. Traditionally a 7 speed cassette can be used on an 8-10 speed freehub with the addition of a 4 or 4.5mm spacer. https://problemsolversbike.com/produ...pacers_-_24987 I don't know any reason you couldn't use your 7 speed cassette plus these 2 spacers on the Kickr but might be worth asking Wahoo. Edit- oops, I see you said "freewheel." If you do have a freewheel (vs cassette,) you'll need to buy a cassette as well.

Try using some spacers from an old cassette.

I've used 11 speed 105, and Ultegra spacers successfully on modern wheelsets so I could use older drivetrains, so I figure it should work for your kicker.

That my friend is a freewheel not a cassette: https://www.sheldonbrown.com/free-k7.html

You could purchase a 7 speed cassette to work but I gotta wonder what kind of bike she is running? 7 speed freewheels are long out of date so it is either something cool and vintage or she could use something a little nicer not from Aisle 10 at WallyMart and you could get a cheaper trainer. Either way check and make sure the spacing will work on that as it is possible the bike could still be 126 spaced (not likely in 7 speed but you never know)

Thanks - it's a new Trek FX1 (3x7), so the spacing will work as it's 135mm. I'm trying to talk her into an upgrade, but she's new to riding and wants to stick with this one for a while until she has a better idea of what she wants in her next bike.

So there are still 7-speed cassettes out there that (along with the appropriate spacers) will allow her to use the FX with the Kickr? That's promising, thanks!

Oooof...freewheels are a vintage affair but not something I would want on a modern bike unless I was trying to make more money off the end consumer. I have seen plenty of bottom end bikes from known brands and most of them these days have all gone cassette. With the ubiquity of free hubs and the ability to find cheap ones easily these days you would think a big brand like Trek would keep up with modern times...ah well.

You can find 7 speed cassettes (or they normally exist in non-covid times) just make sure the ratios are generally the same or smaller so you don't run out of chain.

Not really, still common on the lower levels
https://www.trekbikes.com/us/en_US/b.../fx-1/p/17446/

https://www.universalcycles.com/shop...34&category=42 and https://www.universalcycles.com/shop...0&category=503

Thanks!

I have a Kickr SNAP, so it doesn't matter but I when I was thinking of moving to a wheel off trainer, I ran into the same issue. I sent email to Wahoo support and they said the Core did not support 7 speed rear ends. Doesn't mean you couldn't make it work, as others have pointed out, but they won't provide any tech support if you have issues.

Trek Bike
 

My wife also has a new Trek FX1 (3x7) and it makes a popping sound in 4th gear even when you are in 1, 2 or 3 on the chainring.

Hi there, did you manage to solve this problem? Thank you

Yes I bought a new wheel WHEEL MASTER ZAC19 8/9/10-SPEED CASSETTE 700 X 35 BLACK REAR WHEEL and Sram 7 speed cassette plus a spacer and it works and sounds perfect.

In case anybody wants to try this or is wondering if it works: I have installed my 1992 Koga Miyata Exerciser 7speed steel bike on my Wahoo Kickr Core. Of course spacers are needed to fit a 7speed cassette on the Kickr. It was running great, but the jumps between the 7 sprokets were a bit to big for me (if you're an exact cadence guy...). So I switched to an 11speed cassette and chain......and....surprise: it works!!

I'm using:

-Steel frame (126mm original spacing fits on the Kickr with a bit of force)

-Shimano 1055 rear derailleur (short)

-Shimano 1055 crankset (52/39)

-Shimano 7speed downtube shifters (for 11speed you have to switch to "friction mode" because the indexing is 7speed...)

-Shimano 105 11speed 11-28 cassette

-Shimano 105 chain (11speed)

Nicely done, I really like your 7 speed shifters in friction mode!!

The best thing with friction mode: the drivetrain is super quiet since you can fine adjust all the time :)

https://cimg5.ibsrv.net/gimg/bikefor...a135576384.jpg