11 & 9 Speed Bikes on same Direct Drive Trainer

rank_amateur

I’m a bit embarrassed to ask this after 40 odd years of cycling..... I’m contemplating buying a direct drive trainer, like the Tacx Neo - for me using my 11 speed, 105 bike and possibly for the Mrs using her 9 speed, Sora bike. Do I need to swap cassettes/spacers every time or would her bike fit and just align with 9 of the 11 available cogs in the cassette? Thanks.

webboo

I suspect that a 9 speed chain would be too wide for an 11 speed cassette.

Matthewfalle

isn't 11 speed cassette spacing also different so shifting won't work?

what you guys need is a turbo only bike - you just need a frameset, prop for forks (not even a front wheel), and cockpit/drivetrain - no brakes etc.

so long as the bike fits you both as close as dammit its a winner and should cost you barely next to nothing.

lemonenema

no it wont work at all! youll definitely need to use a different cassette to match the bikes gearing

keef66

You clearly need to upgrade your missus's bike to 11 speed.

lemonenema

hell no! 9spd all the way man

rank_amateur

Thanks all. Yeah, I suspected the spacing at least would be different.
A dedicated turbo bike between us wouldn’t work, as I’m a foot taller, and upgrading her bike to 11 speed would deprive me of stuff for my fleet....so that’s not gonna happen
No big deal, I can swap cassettes easily enough.
Cheers.

whyamihere

If you just want to use erg mode then you can make it work because you don't have to shift, the trainer just adjusts the resistance regardless of which gear you're in. For sim mode, you will need to switch them around.

yellowv2

Unfortunately I think the chain will still be a problem.

Matthewfalle

yup - the 9 speed chain probably won't work with the 11 speed cassette due to sizing and vice versa.