MTB on the trainer?

Hello all,

I’m a triathlete (who dabbles in cx and some other single sport racing) training for an xterra. I have always left my road bike or TT set up on the trainer, but now that I’m training for a race on a mtb I have been looking into putting the mtb on the trainer (basically impossible to ride outside this time of year unless you are riding a fat bike).

Do other people feel like it’s important to train on the bike that they plan to race on? The geo difference between my xc bike and my road/TT bike is pretty different and the xc bike is a hardtail.

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We’ll worth it. Most trainers accommodate mtb’s without too much trouble

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Yes, IMHO you should train on the bike that you want to ride on.

Just flip your premise on its head: assume you had a mountain bike in your trainer, but your next A event is a regular triathlon. Would you want to put your tri bike on the trainer?

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Alex Wild on the podcast states that he trains entirely on his MTB on the trainer as he’s solely focussed on MTB races.

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personally, I really don’t care… MTB riding outside is not comparable to indoor riding on any type of bike… there is so much more happening on the trails…

but it might be different if you race the more flat/straight stuff, and I don’t race that often too.

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It’s less about simulating a trail and more about position/fit on the bike. This is relative to hip angle, arm position, power output, etc. and how your muscles and mind adapt. It’s likely subtle, but if you spend a significant time on the trainer it could be an issue, especially MTB vs TT bike since they’re vastly different.

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Super easy on a wahoo, I’m assuming most are the same. For wahoo, just flip the thru axle adapter on the non drive side and find a 12 speed cassette. I typically have my road bike on mine but use the mtb when getting ready for a mtb specific event. Very similar to your situation that mtb riding outdoors right now is challenging at best.

yes, I get there is an advantage on paper, and for some it might be an actual advantage.
I think it’s more a thing for road riding and different road bikes, like endurance, race, tt. where the position is different, but the way you pedal is not.
On the MTB, the way you pedal (outside) is way different, much more spikes in power, + you have to pedal from many positions, in/out of the sadle, shifting your weight around, trying to let the bike follow the terrain instead of the rider bumping around etc.

Your also right about the time on the trainer, for me that’s only 2-5 hours a week, so -for me- the trainer is a tool to get my fitness up, and the outdoor rides are a way to train my technique and put the fitness to use…

So again, depending on your situation, it might not be that relevant. If you’re on the trainer for 10+ a week it’s more relevant, if you can’t ride outside on your MTB at all (as @TyBauer73 mentioned) it might be more relevant.

But If your not that experienced on the MTB, I would really suggest to do some more outside riding, there is a huge difference between putting power on a smooth surface and power on rough terrain, and then we are not even talking about cornering and other skills. Also riding efficient comes with experience, so the more hours you can get outside, take it (unless it’s already 2nd nature)

I see both points but I default to your choice as I’m too lazy to bother ordering parts to get my 120mm bike on the trainer. All of my more specific MTB training is done outdoors where it should be.

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In my opinion this depends on at least 2 factors:

  1. Are you comfortable and “at home” on your mountain bike
  2. Will you have at least a few weeks after the snow melts until your first race to ride the mountainbike outside?

I would be more cautious if I were going the other way around. Doing all the training on a comfortable mountainbike and then only race on a tri bike. I do all my outdoor rides on XC or Enduro bikes, and only train on the trainer with a road bike, and have zero issues.

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Interesting that there is such a wide range of opinions. I have all the stuff to put the MTB on the trainer, and did a week of training on it. Definitely feel like I’m working different muscle groups. Had to dial down the the difficulty on the first workout.

Does anyone know if this was discussed on the ask a cycling post podcast at any point? Seems like it would be a good discussion.

This could also be the difference in the front chainring and gearing. The momentum in the flywheel can make a difference and there’s a long discussion on the forum regarding this.

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Yup, I’d want to know the exact trainer and gearing in use for each setup.

If gearing is even mildly different, it’s likely that a separate FTP test is appropriate.

Definitely keeping an eye on this thread. I bought a new MTB (Epic Evo) last year and want to train on it.

Currently my old road race bike is setup on my Neo 2T trainer with a Shimano cassette. I have not switched cassettes since I bought the trainer so curious if I still have accessories to make this work. So will need to buy a spare SRAM cassette if I can make this work. Also when people are using their MTB, do you lock out the front suspension? Is the front wheel holder needed?

Thanks for any feedback!

I lock out f/r suspension and a front block is not needed (Kickr Core). Block may be needed to bring it to level but would be trainer dependent.

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The gearing is definitely different.

I always have felt the most comfortable in the big ring on my road bike, middle of the cassette in the back to make the chain line straight.

The MTB has a 30 front chain ring, so getting a straight chain line is something like a 18 in the back maybe.

I guess I haven’t gone down the rabbit hole of how gearing effects the ftp test but I have to imagine that the difference in position is a bigger driving force? I guess I’ll get used to the position for a week or two and then retest.

  • Yes, higher gearing = higher flywheel speed. I hesitate to use terms like “easier” or “harder” as some do, so I just state that it is “different” in terms of feel and FTP test results.

  • It’s likely that small changes are irrelevant. But a 50t vs 30t driver will be a HUGE difference in flywheel speed and I believe lead to a different FTP result. You are changing a variable in the system, and I think that level of change warrants a new FTP test.

  • At the very least you may confirm there is no difference, but I’d wager that you will see a difference in the final result. And using that from this point forward on that same bike is the “best” option.

  • Depending on the actual workouts you have on tap, I’d suggest moving the testing up in priority if you are into more hard work at SS or above. It may not matter if you are doing mainly low intensity Endurance and Tempo work, but top end stuff matters when you could be talking about FTP differences.

  • Considering you feel the difference you do, and I don’t think it is the position at play more than the gearing, I think a test sooner is a better plan.