Mountain bike gears too small for Zwift?

I’m completely new to all aspects of cycling. I have a mountain that I just setup on a Wahoo Kickr and Zwift. I wanted to try out the FTP training and noticed that in my fastest gear (I don’t know the correct terms) I can only manage about 120 watts and my feet are spinning so fast with little to no resistance, like I’m riding downhill and trying to catch up to the speed of the bike. It occurred to me that perhaps mountain bike gearing isn’t mean to achieve high speeds and I’ll be limited by the bike itself. Is this possible or have I got it set up wrong?

If your are in your hardest gear (biggest chainring on the front and smallest cog on the rear) I would think you’d still be generating some good power on an MTB. Is it possible you have it in ‘erg’ mode, and set at a low power level? (In erg mode the trainer will adjust the difficulty to the specified wattage output no matter what gear you are in.) And did you check at the startup screen to ensure that your trainer was properly paired with the Zwift app?

Thank you Jeffrey I’ll check. I’m pretty confident I’m paired up with the Zwift app but don’t know if I’m in “erg” mode, that’s a new term to me that I’ll have to YouTube search to get an understanding to make sure I’m not.

make sure you do some calibration spin-downs! preferably with the wahoo app first, then using the in-zwift one later.

this may be a redundant question, Did you pair it as a Power source and controllable?

It need to look like this. and if using ANT+ pick the FE-C option

Also set your trainer difficulty to 100%

Hi I think this is a still remaining problem with Zwift
Base Resistance, Small MTB Gear whatever. I’d wonder how many are there with MTB gearing forced to ride in ERG Mode because permanently spinning out in the flats. Zwift is fun in ERG mode too, but I think it’s a pitty to give as solution “buy a cheap road bike” to use simulation or take part in races.
I personally want to train on MTB for Triathlon, so switching to Zwift’s new MTB mode is not a solution for me. So I will pedal on in ERG mode…

Why not buy a bigger chain ring?

It’s the problem of the new 1x11/12 MTB setups.

But yes, a trainer offset slider would be very good.
You don’t need to ride in ERG, you can just configure a workout that just has a “free ride” block in it. Then you can set an incline for that in the companion app

Thanks Ben, this could be the solution I will test if the incline is the slider I was searching for, hope this works in the flats too. I do not have a 1x11/12 I have a 2x something but still its not comparable to racing bikes, at 45kmh you spin out.

If using an MTB on zwift with a Kickr, you can use the wahoo app to add headwind. Come out of the app and it remembers the setting until you power cycle the trainer so you can use it with zwift with extra resistance on the flat.


but if you do that do you still get the resistance changes on the hills or does it keep it at that same level?

I wish Zwift would add a second slider that lets you offset the resistance level for off road gearing. Being a xc racer I would prefer to use my mtb on the trainer, but the 1x11 gearing means I’m nearly always running the hardest gear on the flats and sprinting is out of the question…

It should just give an offset from memory.

cool will give it a try this week :slight_smile:

Did a longish ride. It seemed to work (sort of) but the resistance felt like it was constantly trying to adjust between the headwind setting and the Zwift setting, felt unnatural. The only other option would be to stick it in dumb mode, but most likely I’ll probably go back to the road bike once its back from the workshop :expressionless: ah well

Try to use only low values in single digits and make sure to come out the app afterwards then connect to zwift.