Ambient Temp and Effects on Smart Trainers

I stole this from the original post by @Wad06, because it is a great question and worth discussion:

I have a Kickr Core. I’m thinking of moving it to a room that will be 40-50 degrees. Wahoo says that should be fine.

  1. Does ambient temp have any effect on smart trainer workouts?

  2. Will I need to calibrate more, warm it up longer, etc.?

  3. Should I expect any difference in my own performance and compensate (raise or lower FTP)?

I’m also curious about this but my situation would be a kickr in a room about 26C:

I perform a spindown after the longest workout of the week (typically 1.5-2hr). I notice that the kickr flywheel is hot to the touch. When I perform the spindown in the wahoo app, it would say temperature is around 50C. Would performing the spindown when the kickr is hotter than usual would have any effect on accuracy?

Thank you, Chad. I got caught up with the other thread and work. Didn’t get around to posting this one.


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I may be wrong, and it could be trainer specific, but along the lines of power meters, I fully expect that trainer makers are tracking and adjusting power reporting based on trainer temperature.

The mere fact that you see temp in the calibration is an indication that they likely track and adjust with it as a reference.

Check with each manufacturer, but the common recommendation is to do a “hot” calibration. That means running the calibration after 10-15 minutes of use (not often defined for resistance level), to heat all the bearings, running gear, and electronics to their “operating temp range”.

When you do this, it takes the spindown time and temp into whatever magic calculation happens behind the scene.

All this gets to the point, that as long as you are using the trainer withing the specified temperature range, I feel it is appropriate the trainer to report “good data”, within it’s stated power tolerance range. I would like to assume that the makers have done appropriate testing at the limits.

I don’t know of anyone who has actually pushed any trainer to the ends (high or low temps) and reported comparisons to actual power meters. So we are at their mercy, unless we have power meters for testing.

I have been chasing some significant power mismatches on my 2016 kickr (ie up to 17 % off, and highly variable error within one ride, both reading high and low) I was having these problems when doing the workouts in my garage which at the time was about 85F (30C). I tried all kinds of things - checking for light interference on flywheel sensor, checking/adjusting belt tension, numerous factory spindowns, a fan plowing on the trainer, and a different power supply. None of these changed anything, and I verified that the kickr was wrong by comparing it against 2 different power meters (Assioma and P1 pedals).
Now that winter has come, the garage is about 55F(13), and the kickr is back to performing great - within a few percent, and the difference is generally stable. It’s now been several weeks of working properly.
I’d love to be able to reproduce the failures at high temp again, but I can’t control the temperature in the garage. I suspect my problem was electronics related, rather than some mechanical difference due to temperature.

I don’t know if my experience is due to a design issue and that high ambient temps will make all kickrs of that vintage unreliable in those conditions, or if this is something that more generally affects all of them. From what I can tell the Kickrs don’t really have good cooling for their circuit boards, so this could be a general problem.
Do any of the trainer vendors make claims about operating conditions? I think most electronics have listed operating temperature and humidity ranges, but I haven’t looked for these for my trainer.
I just got a H3 which I will be trying out soon - hoping for better results this summer.
I would generally be more concerned about heat rather than cold.

I logged a ticket now with Wahoo. I have a Kickr Smart trainer and the fly-wheel cover this evening after an hour workout was extremely hot. I’ve never noticed this before but then I’ve never felt the fly-wheel cover so I don’t know if it’s a new thing or not. Too hot to keep my hand on it. Not sure if this is to be expected but the room temp generally is between 20-30C during the workout.

Yup, heat there is generally normal. Heat is the expected byproduct from the resistance that the trainer is providing.

It’s Impossible to say without proper temp measurement if yours exceeds the usual temps, but you don’t want to be touching or holding it after being used for anything intense.


I’ll get one of those temperature stickers with different colour gradients that you usually see on fish tanks. Will put one on the side of the flywheel cover to see what is a regular post workout temperature for the cover.

I am a bit confused as to what your concern is here… And also not sure exactly where you intend to place the thermometer sticker but if it’s getting too hot to touch, then it is out of the range that an aquarium sticker shows anyway.

Parts of trainers get hot with use as mentioned by others above, it is normal and I assume that the mfg have designed for it, and compensated in terms of accuracy with either temp sensor feedback or other compensating measures in the software.

If you’re still curious, an IR thermometer would be a better way to get temp readings, they are useful for other things around the house too. Be mindful of emissivity and proper usage for accurate results of course.

Not too concerned, just that I’ve never noticed it before.
I don’t have to pack away my Wahoo after, so the bike stays on, thus would have never touched the turbo just after a session.
More curious though than worried and the Power readings are still accurate.
You’re right on the temp stickers, they don’t go higher than 40C.
The IR gun type readers are £20+, so not sure I am that curious.

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Reply from Wahoo

“The fly wheel cover will get hot as this is the part that covers the part where resistance occurs which builds heat. They can get hot at times.”

Yup Yup - in short, the energy (watts) one is pumping out during a workout gets turned into rotational motion and heat.