Power Disparity and despair

I have a stages power meter- single side. I used a dumb trainer for years. Dummy wore out so I got a Saris. It works great however the difference between the Stages and the Saris readings are significant. This isn’t an ego issue. The issue is the disparity in the two power meters causes both to be irrelevant. The Saris numbers are great when inside but aren’t relevant outside. My Stages works great outside but I cannot fix the resistance on the Saris to allow me to use it effectively as a dumb trainer.

I stopped using trainerroad because of this issue. Like everyone, I use a power meter to gauge my effort outside and irrelevant numbers are not helpful by definition.


Welcome to the club. You will find MANY topics here where people have power data devices (trainers and power meters) that don’t match. Some by a little but plenty with larger deltas.

Not sure exactly what you are looking for, but if you still want to use TrainerRoad, and plan to have the bike with the Stages on the Saris trainer, you can consider using TR’s PowerMatch feature, if you didn’t already do that.

This will apply in any trainer mode that you use, where the data that TR uses and you see is the data from the power meter, not the trainer.

I’ll just start with that to see if it solves the issue. If not, there are more complicated ways to address it.

And just to get some more context here:

  • What exact Saris trainer are you using?
  • Do you calibrate the trainer per the recommended process and frequency?
  • Do you calibrate your Stages power meter regularly?

I do all the calibration. I think is an H3? The last one before they closed up shop. I will try the power match. I remembered that after I posted. My question on that is do the outputs from the devices have to be different? One Ant+ and one Bluetooth? Do you run two devices like a laptop and a cell phone with Ant +? I didn’t realize what a sad day it was when my 100 dollar cylcleops trainer died.

That isn’t any Saris model I know.

  • Models that you take your wheel off and mount to the bike to the trainer:

    • Hammer, H2, H3
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  • Models that you leave your wheel on:

    • Magnus, M2
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See the file I linked for the details, but you need the power meter AND the trainer connected to the TrainerRoad app on the same exact device.

  • It may be possible to mix ANT+ & BLE if you have something like a PC, Mac, or mobile device with both connection methods. But there is no specific communication protocol requirement.
  • Just need both devices connected to the same device and TR app for PowerMatch to work.

And for the record, the Saris trainers have an interesting feature. If you plug them into the normal outlet for power but DON’T connect them to an app, they default to a “dumb” resistance mode. This mode mimics a fluid resistance power unit that is progressive in nature.

  • Headless mode (powered on, not paired to any apps) lets you ride with a progressive resistance curve that matches the Fluid2.

I have used it with my Hammer and Magnus and it works well. With that, you could pair just your power meter to the TR app and leave the trainer out entirely. Then you could use it as a dumb resistance trainer. An option to try if you want to ignore the PowerMatch option.

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A cautionary tale: if your power meter significantly underreads the trainer, don’t switch to Powermatch, and then immediately attempt a stretch threshold workout, especially if you already marked your previous threshold workout ‘hard’. It won’t end well. Ask me how I know…


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If power match works it should be fine else do a a workout or some tests where you record the trainer over TR and the PM with Garmin/ wahoo afterwards you can compare the files and check the difference so you can adjust indoor and outdoor workouts accordingly.

I have the issue that my PM on the road bike and the gravel bike are reading different. Not that big of an issue for training but I can’t really feed the WKO5 model with data from the gravel bike because it is so much lower.

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I calibrate my H1 over workout. It’s no help really, but N=1 mine was close enough to my left only 4iii. There’s a difference in the accuracy (1% v 3%), left side only v total power, crank v hub.

Obviously. if it’s a significant difference it’s an issue. But I do think people can get hung up with small differences. Again n=1, I do my workouts inside, and if AI FTP is off due to a difference, AT and PL’s can look after it. My consistency is better having a dedicated trainer bike than swapping on my ones with a power meter!

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