Trainer power reading not correct

Hello guys i have wahoo smart trainer v6 lastest and i usually train on zwift so currently i am feeling that my power is not correct i am using the inbuilt power meter in my smart trainer. right now i don’t have any other power meter so double check it my outdoor power meter has been not working since month’s. And i have calibrated the trainer but still i think my power number are incorrect. Now i am telling this because i know my number for example i can sustain 300 or plus watts for hour but on indoor since i have purchased trainer an traning on that i can’t even hold 200,250 watts for long and i feel like i am doing more than 300 watts. And my friend always tell me that why you number is showing so less in zwift because
We use to train together and we can produce almost same power. he has shifted to far form me so i can’t doub check my powr number on his trainer.

So any idea what is happening?.

It would be really helpful for your suggestions

Welcome to the forums!

Just to be sure we understand, are you saying that you could hold 300 for an hour using your outdoor power meter, but using your Kickr, whether on Zwift or TR, you can’t hold 200? If so, what power meter were you using before you had the Kickr?

Or are you saying that with the Kickr you can hold 300 in Zwift but not in TR?

I am talking about outdoor and i know my number as i have done few races round my country and i can hold 320 watts or so for longer time so I was having dual side power pedal. but it has stopped working 1 or 2 months before since then i have brought smart trainer kickr V6 for my indoor training and i am currently using wahoo smart trainer inbuilt power meter and now i know few people will say that power meter and inbuilt power meter of smart trainer will be different or outdoor and indoor power number’s will he different but the thing there is no difference in the numbers., there can be but not that much difference. & I have talked to everyone my friends in zwift they always say there is no difference and they are producing 250 watts 300 average. So what you think what will be the problem? It shouldn’t be my trainer because i have purchased brand new.

What brand power meter pedals were you using outside before you had the indoor Wahoo?

I’m trying to understand if the outdoor pedals were the problem, not the Wahoo. Also, which Wahoo are you using?

Thanks for replying and helping
so i was using Favero Assioma DUO Dual Side and about trainer i have wahoo smart trainer V6

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What’s your cooling like indoors? Its far easier to maintain power outdoors with natural air cooling and momentum. You could just be overheating and blowing up early indoors.

Not at all exactly i have fan ac and my room temperature is like very cool and i don’t sweat that much so i guess it’s not like that? What you think?

Hard to say and I’m no expert on the human body but I think you need to sweat to cool efficiently, outside you are probably sweating and it wicking without you noticing. I’m not sure if drinking more helps you sweat more you could try that also.

Okay but i don’t know what is the connection between power and sweat i know the number will be different but it couldn’t be that much difference that i am struggling to hold 250 watts

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As it’s a brand new kickr, make sure the firmware is up to date, this can be done in the wahoo app.

If you are still experiencing issues you could then try a factory spin down. (I think that’s what it’s called, it’s been a while since I owned a kickr)

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I’m definitely not an expert but I think the connection is sweat = effective cooling and hydration, and without the latter you can’t deliver the power. I never used to sweat either I’ve upped my cooling (got one of those blower fans that are reccomended) and I now sweat buckets. It could be entirely unrelated though as I had other things going on at the time.

I have heared that factory spin down is bad it will be bad for your trainer as it internals damage and also i have a brand new trainer so i guess that’s not the issue

If you are questioning the data from the trainer, contacting Wahoo seems a step worth taking.

Aside from that, here is a quick list of the common influences to lower power indoors (some already listed but showing again to have them in one place):

  • Cooling: It is harder to get sufficient cooling inside compared to outside. A good number of fans well placed in temperature controlled room are good measures to limit core temperature gain.

  • Power Data: Differences between devices can and do exist in many cases seen over the years. Some is within the tolerance of each device while others stray well beyond. Proper installation, setup and calibration are key as well. We’ve seen some people have incorrect crank length on pedal power meters that can give skewed data. Add in the need to properly torque them for best results as a step that many ignore. Sounds like you have the latest Wahoo trainer and it should be auto calibrating. I’d skip any more than that until you talk with them.

  • Motivation: Some people struggle with the delta between the fun outside and inside being boring by comparison. Stuff like Zwift that you are using can help, but even with the best distractions we can still suffer some lag inside.

  • Inertia: Despite the best trainers in use, the flywheel effect can fall short for many people. It leads to different loading on our muscles specifically since we may have less “help” from the trainer compared to outside. This can vary widely though, since rider weight, riding area, surface type and other factors can influence how similar or different the flywheel effect is compared to outside for each of us. This also relates to the gearing you use coupled with things like “Trainer Difficulty” in apps like Zwift. No simple answer here, but taking a look at these in contrast to your riding outside are worthwhile.

  • Motion: Locking a bike into a vertical plane is not exactly matching outside. It doesn’t matter to everyone, but this is a notable difference for some riders. They like adding motion from simple foam mats up to rocker plates and the like to get more freedom vs the typical rigid setup.


I don’t own a Kickr either, but I would be trying the spin down. One check of calibration and accuracy is not going to ruin the trainer. I know it’s brand new, but that doesn’t mean it came out of the factory in perfect condition.

You had quality pedals and you have a quality trainer. They will differ, but like you said, being off by 30% means something is not right. Can you ride a friend’s trainer and see if you can hold 300 on it? Is it possible the pedals had been set in the app to a higher bias?

Just brainstorming.

For there record, the “Factory or Advanced Spindown” (referenced above) is a different beast than a normal spindown calibration. It is deliberately “hidden” in the Wahoo app with a series of undocumented steps to engage it because it is another level of calibration. I have also read the comments that it should not be done randomly or without consideration since there may be more going on there.

It’s worth noting that some Wahoo documentation has stated that doing factory spindown’s often can cause some damage to the internals of your KICKR, so you should only do one if requested by Wahoo support, or if the regular spindown doesn’t resolve your issue.

Wahoo has hidden the advanced spindown utility in its mobile app, presumably to avoid users accidentally running it too often. They’ve even removed mention of it from their own website, as far as we can tell! Sometimes, though, an advanced spindown is exactly what a KICKR needs. So here are precise instructions for accessing and completing a KICKR factory spindown. (The instructions below apply to the standard KICKR as well as the KICKR Core and KICKR Snap.)

All that to say that starting with Wahoo remains my suggestion for anything beyond auto or manual calibration (not the Factory/Adv version).


Agreed. I would always reach out to support first, but the parts you posted above also agree with my statement that doing it once isn’t going to ruin your trainer.

Bolding here is mine.

It’s worth noting that some Wahoo documentation has stated that doing factory spindown’s often can cause some damage to the internals of your KICKR, so you should only do one if requested by Wahoo support , or if the regular spindown doesn’t resolve your issue.

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