Rollers & Power/Cadence/Speed

Greetings. Super happy Zwifter that wants to mix it up by using Kreitler rollers from time to time. First I’ll explain my current configuration with a Tacx Neo 2T that works well then the roller configuration that is not working as desired.

Zwift Companion App IOS
Zwift Play Controllers
Garmin Tacx Neo 2
Garmin Dual HRM
Bluetooth connections only

Would like to work:
Zwift Companion App IOS
Zwift Play Controllers
Kreitler Rollers
Stages left crank power/candence
Magene Speed sensor on rear wheel (setup in speed mode, not cadence)
Garmin Dual HRM
Bluetooth connections only.

For simplicity purposes I am only trying to prove that I can connect power and speed sensors, to ensure the configuration is not reaching Bluetooth connection limitations with the Zwift Companion App on IOS

It seems that for a connection on AppleTV, either a power or speed sensor may be connected but not both.

Problem with Would like to work:
If I connect the Stages power/cadence sensor I am unable to connect the Magene speed sensor as there is no speed sensor option displayed once a power option is selected.

Now, if I connect the Magene speed sensor first, I select unlisted rollers then the power meter option is grayed out and I’m unable to select.

Is it not possible to connect a crank arm power/ cadence sensor and a wheel speed sensor for rollers ?

Thank you in advance.

Hello @Keith_Cunningham1 , welcome to the Zwift forums! I can confirm that it is not possible to simultaneously pair both a speed sensor and a power meter to one Zwift session. If you have the option to pair a power meter, I recommend always pairing it instead of a speed sensor for the most accurate data in your activity.

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Exactly, why would you want to pair a speed sensor when you have a power meter?

Thank you @Rowdy.
The reason for attempting to use the Speed sensor configuration was to establish tire size for the universal roller configuration. If Zwift is performing some calculations to estimate speed based upon the left crank arm power, I’ll expect it to be good enough for a device that is not offering resistance feedback or speed, like the Kreitler rollers.

Perhaps it is my lack of understanding the Zwift algorithms but, it seems to make sense to me that by combining tire size and speed data, along with power and cadence data of the Stages left crank arm, would provide a more accurate calculation. Anyways, less thinking more riding, thanks again.

It seems like you are attempting a variation of dual recording to establish accuracy.
The issue is you are comparing ZPower to a Power meter.
You can do it but it wont show in Zwift.
Zwift will only let you pair one source and you will have to use another device to monitor the other.

I’m not sure if you can do the following with your setup but I suggest you try something like this.
You will need to get data reported as watts in order to compare apples to apples.
Zwift will convert the Speed data to power for you.
Pair the speed sensor to Zwift using the appropriate Roller selection.

Then pair the power meter to your cycle computer or even Strava.

Ride and compare.

I think you will find the speed sensor will not match with the power meter.
You can then adjust things to try to improve accuracy.

My attempt at this experiment demonstrated that Z Power just doesn’t cut it for E racing or even comparing to your own outdoor efforts.
Ultimately, why would one use ZPower if a Powermeter is available?

A related issue is setting up 2 power meters to confirm accuracy of each.
Again, Zwift will only let you pair one at a time as the Power source.

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