Trainer & different bikes compatibility

Hi all,

Looking to get my wife riding on the trainer with minimum hassle, and my simple brain is struggling.

Kickr Core is setup with an 11-28 cassette, and my roadie lives on the trainer during these lockdown days.

Wife has an old Dutch-style cruiser with a 6 speed freewheel, I’m thinking that will be a pain to get working on the trainer - are 6 speed cassettes even a thing?

Not completely against getting a new bike, when lockdown has passed, she will be riding to work again which would help justify purchase.

Easiest would be a cheap roadie, but wife has no interest in drop bar bikes. I think a hardtail could be an option as she does enjoy the odd adventure race (run, kayak, MTB things) when she borrows a mate’s MTB.

Issue there is cheaper MTBs come with 7 or 8 speed cassettes, I guess easy enough to swap over on the trainer with a spacer, but who needs that hassle a few times a week?

Say we got a bit fancy and went with an MTB with e.g. 30T crank and 11-42 would there be a problem with chain length when on the trainer with 11-28?

Thanks for any tips! I feel like this is one of those things I’m overthinking :smiley:

Hi @James_T I’ve been using my MTB on the trainer for quite some time.

This works really well all round.

And it can be made really easy by just sticking to the current trend of ever bigger cassettes.
10/11/12 … whatever.
The chain length has never been an issue. As the RD picks it all up quite happily.
I’m usually using 28/30 or 32 oval on the front.

What I’ve done is (I’m 12sp)
Get a cheaper cassette - 12sp can be a bit nasty expense wise but there are cheaper ones now that aren’t SRAM XD - and I lob that on trainer.
And the bike has its normal XD cassette.

All I’m doing is unwinding the thru axle and chucking the wheel in and I’m off …

If your going 11sp and leaving a road cassette on the RD of the MTB won’t care. It can deal with 11t so the fact that the biggest sprocket is 28 … it just won’t care.

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Plan would be to leave the road cassette on if possible, because, lazy.

Assuming it would be fine seeing as MTB has cogs just as small.

Just want to confirm I’m not missing anything silly with chain compatibility or anything, as I’ve never had an MTB.

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It is nailed on 100% fine.

I sometimes even use my MTB when it’s set up as 11sp with my 10sp road cassette … it’s absolutely fine.

The inner width of the chain is the same.

Especially if ERG is in use as it then becomes even less of an issue.

(Scenario B I sometimes have is:

  • ancient road bike sitting on trainer using 10sp cassette and 10sp gearing
  • want to do a workout in my MTB (11sp SRAM setup) and can’t be ‘bothered’ swapping stuff over - so I just chuck the bike on and ride

The only thing I am sometimes wary of as chains and cassettes and chainrings all ‘wear’ is that once things get out of sync too much (eg a badly worn chain) it can increase wear. But I just keep and eye on things like that.


I’ve simillar issue a few months ago when lockdown begun. Bought to my wife a cheaper hardtail 7 speed to use on my old kickr17, then I found that I had to replace the cassete from trainner, luckly I’ve found on a local bike shop a cassete 7 speed and the difficult part was to adjust spacers, but the mechanic did a great job . Waching that from a safe distance while enjoying a coffe that did not looked too complicated. :wink:


Yep, that’s what I want to avoid if possible, the hassle of swapping cassettes and spacers on the trainer a few times a week every time we swap bikes. Plus the possible need to re-index gears when putting the wheel back on.

Sadly no bikes going second hand besides 7 speed lately.

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