Power Meter versus Turbo Trainer

I’ve had more consistent trainer vs. power meter results after warming both up for 10 minutes and then calibrating.

i now question my trainer power for the last two years because I never warmed it up before calibrating.

Fair point, I’ve noticed huge temperature differences in my KICKR before and after use. Before use it’ll be at room temp (usually around 20ºC) and after a session it often above 40ºC. That has to make a difference…

Most power meters have temperature compensation, and I’d imagine the Kickr is no different.

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i had a different experience. My Tacx Neo2 had lower power readings over my Stages LR and i posted a similar question before (but with a different power meter):

As we’ve seen the reports about shimano cranks and funky power readings from @GPLama , i opted to just use the neo2 power on my trainer rides.

You can’t assume this stuff if you want the most accurate readings. I’ve only had indoor power for the last three years. I just got a Stages. On first outing to do a 20 minute FTP I struggled and power was way down.

I late found that calibrating after 10 minutes of riding makes a large difference. Stages says in their manual that there is temperature compensation and they also say to calibrate every use for best performance. From my experience the later is required. It could be that the temperature differential between inside and outside is too great for the compensation.

Bottom line, if you are trying to compare do everything right, warm them up, calibrate and then see how far off they are.

Yeah, you have to calibrate a Stages on every ride. But when you calibrate shouldn’t matter that much. I’ve been riding a Stages for years and can’t say that when I calibrate it has made a big difference.

Tried that and my Kickr 2017 wheel-off didn’t always using the ANT+ power meter. Did maybe 30 rides and compared to Garmin recording. Gave it a chance and couldn’t trust it. One reason I went back to PowerMatch.

“smoother, more artificial experience” is what I found. Smoother? Yes. Have never finished an outdoor training session or hard group ride and said “if only the power was smoother” :wink: Power fluctuates when riding outside. Train more like you ride outside, don’t train to make prettier graphs. Your FTP is an estimate, zones are estimates with fuzzy endpoints, and your body isn’t a robot. Something to think about :thinking: :biking_man: :slightly_smiling_face:

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I mean smoother transitions. Not a smoother graph. I even addressed the artificial smoothing in my next reply.

hey not picking on you, in the real world what is the value of a smoother transition?

in any case, my experience has been that any transition (e.g. smoothly bridging a gap) is more neuromuscular and teaching the brain and body to work together. Both on the trainer and outside.

completely agree on turning off Erg Power Smoothing - don’t let your trainer lie to you.

I mean, I don’t want to wait 30 seconds for my 2-minute interval to hit the specific power? That’s really all I’m saying, man. You’re reading way too far into it.

I’m seeing about 3 seconds with TR PowerMatch and Kickr wheel-off, have only seen 30 seconds when something is really wrong.

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I haven’t really tested this since I got my Core, but I had lots of issues when I had a Snap and this is what fixed it. So I’ve been using it ever since. It works well for me. PowerMatch is fine too, but I like the native option just a bit better.

Yeah Snap (tire) and Core (no tire, direct-drive) will have different experiences. What I found is that if Kickr fails to connect to ANT+ power meter, you won’t know unless also recording with bike computer and comparing after. And I want a single source of power truth for inside and outside. And TR’s PowerMatch reliably delivers on that.

And then the whole “make it more like riding outside” that is personal opinion and based on coaches always telling us to make training more like our event.

Have a great day!

At the moment, the only way to get L+R total power from your Powertap P1 pedals is to pair via ANT+. When paired via ANT+, we capture power readings from both the left and right pedals, but when paired via Bluetooth, we can only take the left pedal power and double it.

We hope to improve on this in the future by supporting L+R power via Bluetooth, however, I do not have an ETA at this time.


Thanks, I’ll have another look.

Unless your Neo is faulty it would be more accurate than your Stages.

If you have one power meter, you have one right power meter. If you have two power meters, you have two wrong power meters :thinking:


I have the exact same setup (kickr core and 4iiii) and I went through the same experience… power meter read 20watts lower.

Having tested and since trained using powermatch these issues have been sorted. To stop the power spiking quite so badly try using the small front chainring. The slower flywheel speed seems to help powermatch although it does make for a different training experience as you have much less inertia from the flywheel.

My FTP on my Kickr Snap was 298W in Feb using the ramp test and in built PM…haven’t tested it recently…can’t be arsed as I am just riding my bike in the sun at present as there is no racing. Anyhow my average power for a 54 min tt in my only race this year in March was 270W - measured with my pedal based PM on my aero road bike (didn’t use my tt bike for that race…probably won’t get used this year). I know this is lower but I think the ramp test over estimates FTP as I don’t think I could hold 298W on the turbo for an hour. That said it does scale ok for workouts as I have no issues with doing SS intervals of 20mins @ 270-280W or VO2 @340-355W. I just use the ramp test for winter turbo work and then when I start racing use what I see from my first tt and try and push it up a bit from there…Power doesn’t have to be accurate - it just has to be consistent for you and your training…that said if you own lots of different PM then it could of course be an issue.

Yes, I don’t doubt the readings, it’s just that the Neo captures the whole power output, stages is L only. Aside from maybe a few % drivetrain loss the difference is in my legs. No problem, I just figure it’s better to use one power source both indoors and out.