Speed on Zwift for zPower (that’s what you are using) is estimated buy using your rear wheel speed and the power curve of the trainer you chose and that is converted to watts, with those watts, the weight you entered, ingame bike used, ingame drafting, and virtual elevation changes your ingame speed is determined.
Your ingame speed and the rear wheel speed of your bike will hardly ever be the same.
Hi Gerrie Delport TeamZF, no bike computer, but 3 kph is about the speed of someone walking, while I am pedalling to the full extent of my capacity!
Hi Paul Allen, thanks for explaining that, so, if I may, Zwift calculates the power and then “reverse calculates” what my speed would be if the simulated conditions were real including my weight, the terrain inclination, etc… I guess that it makes some sense, but I would strongly recommend that, somewhere, you put a gauge showing the actual data being generated, just so users can make sure that their equipment and/or Zwift are not broken.