Duration/intensity of warm up for Kickr before calibrating?

I’ve got 2 bikes with 4iiii PMs that read higher than my Kickr. I want to do a quasi-scientific test to see if they’re both off the same amount from my Kickr (then I could trust them both) of if they’re off different amounts (then maybe some scaling is required).

I want to do a proper warm up for the Kickr before calibrating it…is 10 mins easy pedaling enough? Should I run through different power/cadence ranges or does that not matter?


If you are really aiming to do a power data comparison, I would suggest something like the typical TR warm-up, not pure easy pedaling. Get it up to your Threshold or so, even if just for a minute or two.

As to the “power/cadence” question, ignore cadence. You do want to test at a range of powers though, because there can be different data spreads between devices at different wattage. You will only know that if you test below, at and above Threshold.

Related to that, most smart trainers are known to have different data reporting (generally less accurate) as the flywheel speed increases. A quick check of GPLama’s latest Kickr test will show you what happens. That issue can be one of the many reasons people see splits between trainers and power meters.

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In a quasi-scientific manner I would replicate the duration and resistance from an advanced spindown. In that case you would be getting what the manufacturer considers ‘correct’

That’s an interesting video. Sounds like the newer Kickr has an offset or estimate for drivetrain losses? I don’t think that’s the case for the Core, right?

Thanks Chad!!

  • No, no, no… that delta at higher flywheel speeds is NOT a good thing or a “feature”.

  • It is a problem present in most current smart trainers, because their method of estimating power is not properly adjusting for the variation from low to fast flywheel speeds. If it was “working” as we all would like, there should be NO separation between a typical power meter measurement and the one at the trainer.

  • Well, if you mean that it does or does not have the “feature” you mention for drivetrain losses, that’s not obvious.

  • Shane and others have only implemented that flywheel speed testing in the last year or so. And since most of the Core reviews predate that, I am not sure we have current data with that same test. Even without that, I am pretty certain that you will see the same problem in the Core as we see in the full Kickr (and the Neo, Hammer, etc.).

  • As I said, this is a symptom of a problem resulting from an oversight that the trainer makers are not testing their units at the extremes. All this despite the clear evidence shown by Shane and others, that there are issues here. It’s a broad problem that we have yet to see get addressed by any trainer maker.

Ok makes more sense…thanks again

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