Converting a MTB bike cassette size

[livpoksoc]

Trying to find a way to use both my MTB and Road bike on a smart trainer. I have a 10 speed cassette on my road bike and smart trainer, but by MTB has an 8 speed group set (with triple front ring). Is it as simple as changing the cassette and chain to a 10 speed set up, or are the extra considerations for the type of bike that make this changeover more tricky?

 

[vickster]

Maybe derailleurs are speed specific too?
Why not just use one bike on the trainer?

 

[C R]

Maybe derailleurs are speed specific too?
Why not just use one bike on the trainer?

And more importantly, the 8 speed shifter would only be able to access 8 of the 10 cogs, but in reality it is unlikely to work, because the shifter pull will be wrong for a 10 speed cassette spacing.

 

[Ajax Bay]

To be frank, if you feel the (must) need to use both bikes on the turbo trainer (assume you'll be prepared to put the 8sp cassette back on if you go for a ride on the MTB), you could swap the MTB cassette for a (?old) 10sp cassette (NB with spacer) and put up with a bit of misalignment with the gears when you're on the trainer. The 8sp chain will not be great (on a 10sp cassette) but it won't jam (ease off when changing gear). The chain will probably be OK on a specific sprocket and one either side, plus you can use the triple to give you 9 different gears.
You're not going anywhere, after all. Success will depend on 'putting up with it' thresholds.

 

[livpoksoc]

No worries. Dumb idea. Sundays...lockdown...does things to the mind.