Cadence & power dropping out at high cadence

I started using TrainerRoad about six weeks ago with my Stages single-sided crank power meter on a mag trainer. I’ve found that when I hit about 170RPM both cadence and power drop out and just display zero during a workout. As soon as I drop the speed down, power and cadence are displayed again. When I review my workout it recorded zero for that period.

It’s a relatively new battery and battery life is reported fine. I calibrate before every ride, and have tried moving my iPad directly next to my cranks with the same issue. I’ve also moved the meter between two bikes on the same trainer with the same result (converted my hybrid into a somewhat permanent trainer bike so I can stick with this structured training thing!)

Side note, when using the Stages meter outside with my Garmin Edge I’d usually max out around 1,240W. I did a quick free ride test tonight on the trainer and topped out at about 1,029W. Of course… this was directly after doing Tallac with 45min of sweet spot. But it makes me wonder if it’s normal to see a difference in power on a mag trainer vs. outside - it’s a crank meter so it doesn’t immediately make sense why I would…

Thanks!

Sorry I can’t say much about the cadence, although it sounds like a issue with the power meter. Is it still in warranty? It certainly wouldn’t hurt to put a support ticket in to Stages.

As for power, it’s not unusual for max power to be different inside and out. Are these efforts out of the saddle? Some people do find they can’t do the same numbers in a sprint on the trainer, probably, at least in part, due to the fixed nature of the trainer. Also, like you said, it’s not really a fair comparison anyway if one of those efforts is after a tough workout.

Here’s an example:

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That’s quite a cadence to hit! I’m wondering if you’ve hit the max cadence for the Stages PM??

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Definitely curious to see if other athletes report something similar here on the Forum, BUT. You should definitely get in touch with support so they can look at the log of your ride and the exact moment of the dropout to see if there’s a device or connectivity issue.

You can email them at support@trainerroad.com, or submit a request online, make sure to include your TrainerRoad username, the devices you’re working with and that context above (or even this Forum thread link!), and the workout where you experienced this issue.
Sorry for the trouble, the team will for sure sort you out! :raised_hands:

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Before I used Trainer Road and its powermatch, I’d find elite’s power match would match my Be Pro S power pedals (as it should) until I upped the cadence there was a large gap between them at 140rpm. In Trainer Road though there has been no drop out however.
Whereas on my other bike last night with a 4iiii single-sided crank power meter. On my short form sprints up to 162 rpm it would stay there and then as soon as I started to drop in cadence (still turning the cranks) power/cadence would drop out. Maybe its something to do with crank arm power meters :thinking:

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Thanks for the replies! Interestingly, I did a bit of reading and found that the Gen 3 Stages power meters have two other options for calculating cadence: a built-in gyroscope (disabled by default) and an external magnet. I’ve just been using the default accelerometer mode.

Before reaching out to TrainerRoad or Stages support, I’m going to gather some more data. First, testing and recording to my Garmin to determine if the problem is specific to TrainerRoad or not. Then, testing the gyroscope and/or magnet sensor.

I’ll share my results in case anyone else runs into this issue or is just curious.

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I have definitely narrowed it down to the meter and not TrainerRoad!

Multiple tests with the Stages app, Garmin Edge, and TrainerRoad bear the same results. As soon as cadence hits ~165-170RPM, power drops to zero, then cadence drops to zero ~1 second later.

I tested in gyroscope mode with the exact same results.

Stages support has been contacted, and awaiting a response!

Gen3 dual-sided Stages and Kickr wheel-off trainer. Recently did 5 short sprints on the trainer but 155-160rpm is my best effort. No issues, and I can’t recall ever exceeding 160rpm while putting power down. Sorry I don’t have any data to share other than confirm it doesn’t happen at “lower” (<165) cadences.

However when doing single leg pedaling drills, it takes about 25 seconds for right side to start sending power/cadence data. I’m doing 50 seconds on each leg, so switching to the right leg means I lose half the interval data (not that I’m actually looking at power/cadence, it’s just annoying).

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I searched WKO and found a few workouts this year with max cadence above 165rpm and they look normal. At the end of the sprint I hit 168rpm for 2 seconds before shutting it down. Like this one:

Always running out of gas at 160-170rpm, and shutting it down.

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Thanks! Ha, as if single leg drills weren’t frustrating enough. I’m not even sure I’m doing them correctly with a single-sided meter. I try to double the power I’m supposed to match (since power is multiplied) then do the right leg by “feel”. It has definitely woken me up to the reality that my left leg is nowhere near as strong. I figure whenever something is particularly challenging/annoying it’s probably because there’s lots of room for growth.

It’s a weird problem but very consistent. Hit 165-170RPM, power drops out, then cadence a second later. The highest it recorded was 172, but the other 4 tests were 165-168ish.

stagestest5clip

I’m pretty close to maxing out, but still have some spin left I think… it’s not exactly ruining my training but I noticed it when I was doing a sprint and now it’s going to drive me nuts!!