Repurpose old mtb for dedicated trainer bike

I am using my road bike on the trainer. Being a father of 3 and 7 year olds and living in Norway I need to be able to do trainer rides all year around. I am now using my road bike on the trainer, which does give me an extra hurdle when contemplating outside workouts. Having to take the bike off the trainer, put in the wheel an realign the gearing is easy, but it does still take some time. I have my wifes old mtb that is a size to small for me in the garage just waiting for a chance to leave the household. Is it a good idea to repurpose this to a dedicated trainer bike? Crank length is correct, I probably can copy my seat position and I guess an insanely long stem vil put the bar in the right place.
Anything I haven’t considered?

I just ride MTB, so I did a similar thing. I found a special thick slick tire, I have had no issues except the gearing range on an MTB is wider so there are times I feel like I am between gears. I may buy a different cassette.


I had to get my frame repaired so put my old hard tail on the trainer. It’s going to stay there purely for convenience since it doesn’t get as much outdoor time. I tried to get saddle to crank and seat to bar position same. Sitting on a trainer it doesn’t have to look good but if you can get it to fit why not. Depends what kind of trainer you have in the main part, sounds like it could be direct drive from your description - mine is too. It does work and makes it far easier to go grab a bike if you can get outside - it’s always ready. :grin:

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Do this. I bought one with fewer steps between cogs than I use outside to be able to keep the RPM where I want it and keep the power where needed.

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Same here with my touring bike.

All I can say is I also did exactly that - wheel on trainer.
Regarding position check BB to saddle nose as that was out, but other than that all is adjustable. If you can’t get a sufficiently long stem lift the front wheel and adjust saddle angle.
Great re-purposing.

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Also, make sure to check crank length. Many MTB bikes are sized with a longer length compared to a similarly sized road bike (because there is no 172.5mm length in MTB, and mid-sized roadies commonly use 172.5mm).

So make sure to account for that if you are using the same pedal / shoe combo. And if you are using a different combo, that is cause for adjustment. Not to mention that a different saddle may lead differ settings.

All that is to say that making the MTB “the same” may take some more consideration than simple dimension matching.

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