We don’t take speed from the speed sensor, we convert watts to speed. So in this case it is funny speed>watts>speed. So wheel size does not matter to our app.
As I am sure you are aware the speed of your wheel inside the house, maybe totally irrelevant to outdoor speed. Now with good fans inside if your heart rate is similar for speed indoor and outdoor that means your indoor speed is semi-accurate. In this case there is a problem with the virtual power curve you selected in our app. If you don’t care about power accuracy and only speed accuracy we have an adjustment you can do to lower your speed coming from our app.
But this will mostly affect higher speeds since it is drag coefficient. Getting the virtual power closer to accurate would be a more accurate method.