Calibrate a non-supported Indoor Cycle

Hi all,

I currently have a (non-supported) Indoor Cycle (FitBike Race 4) which can be paired to Zwift via Bluetooth as a Power Source and Cadence.

Since it’s non-supported, I cannot calibrate on the Zwift app (I assume) since I don’t see a wrench icon next to the Power Source once connected.

The manufacturer of the Indoor Cycle also doesn’t have an app, so my question is if someone knows if there’s a “general” app I can use to calibrate?

The reason for this, is since the kph speed is way too high in Zwift compared to the kph speed I see on my Indoor Cycle’s display (which one is pretty accurate).


Speed in Zwift and on your bike are both simulated numbers based on (hopefully!) the power/wattage you are putting out. Calibration is generally just for improving the accuracy of the wattage output. Zwift uses that wattage number to create the bike speed based on the simulated world you are riding in and your body metrics. So, if you are climbing the Alpe, your Zwift speed will probably be much lower than the speed on your bike’s display since the bike has no idea that you are “climbing” and probably has it’s own built-in simulation based on different riding conditions. Probably a flat road. Hope that makes sense.

Hi @J_Terrell, first of all thank you for getting back to me. And yes, I understand that Zwift simulates the speed depending on the in game situation. However, I am referring to a situation where I am on a flat road and just start cycling… I easily hit 40kph within seconds without sweating. And the display on my indoor cycle just tells me 15kph…

I wouldn’t be too confused if the difference was a couple of kph, but this is just out of reality…


Agreed, that is a pretty extreme difference. Without knowing how your FitBike is simulating the speed it’s hard to say what is happening. Does it have its own controls for changing virtual incline or other simulation parameters? Also, does the bike seem to have different speeds when using Zwift vs. in standalone mode? Zwift does send cycling simulation settings to trainers that use the Bluetooth FTMS protocol (and maybe others) so maybe your bike is interpreting those differently?

I assume it is sending over inflated power number to Zwift.

Best to get power meter pedals so you have correct power numbers.

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On the indoor cycle itself I don’t have any modes or change I can make. So, it seems not much else I can do at the moment, other than purchasing a different sensor.

Is there any difference in accuracy between a power meter pedal sensor and speed/cadence sensor?


Yes, power meter pedals are accurate (most ±1-2%).

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Just curious, what kind of wattage is Zwift showing when you take off and hit 40kph?

Speed sensor on a spinning bike will be very inaccurate, it is not worth going that direction.

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