I have two unrelated questions on tracking performance.

Speed question, specifically as it relates to a Kickr Bike. When you begin a video and Bluetooth connects to the bike, you have two speed options to choose from. One is the speed the bike records and the other is the Wahoo calculated speed. For those who have a Kickr Bike, any feel for which might be a more accurate representation of what your effort would yield in speed out on the road?

Power question, specifically calculating power when riding out on the road. I don’t have a power meter so I don’t have anything that calculate power when I am out on the road. Is there a calculator out on the web or is there a formula for calculating your power? I have the usual info to work with; distance, time, total climb.

To connect what @TrapMeSuf said directly to the OP’s question, I think (but am not positive) that speed calculated by SYSTM is calculated from power ( using @TrapMeSuf’s equations). I think that speed from the bike is calculated by multiplying the RPM of the flywheel by an assumed wheel circumference (which you can probably change in the bike configuration—at least you can with a KICKR trainer).

I don’t have a Kickr bike but the gen rec is use SUF/SYSTM speed. It’s a more accurate representation taking into account the effort required and will result in more accurate mileage if indoor mileage matters to you.

Fwiw, I’d suggest picking up a single sided PM for outdoor riding. You can get one from 4iiii, or Stages in the $400 range, or a PowerPod for a bit cheaper.