First, the world will not end, your power outputs (watts) are probably accurate as they can be.
I motivate myself with charting the ebbs and flows of data. I am a newbie to bikes. I am riding my wife’s on a Saris Fluid 2 stand, with a Saris Speed and Cadence sensor placed on the rear tire hub (duh). The bike has a 37-622 tire that is not listed on the Zwift app. POSSIBLE DATA ERROR!!! I pick 32-720c on our Zwift app.
The most accurate data is the Watts. It knows how many times the wheel goes round and the amount of constant force the Saris Fluid 2 is creating. That is what I care about most, so SMALL DATA ERROR that I can not peel back further…
Speed is an estimate of how many revolutions the wheel is turning and the circumference of the wheel. Remember Speed = the number of rotations an hour times the circumference of the rubber on the wheel. My wife’s tire is 2200 in circumference, we picked one that is 2155 cc. In summary, I can live with the difference.
Cadence is how many times a foot completes a full circle in a minute. When I pair my speed and cadence sensor to Zwift for Cadence and to Speed Power, it is close to meaningless. Might as well turn off that pairing or get another sensor. After a month, I now ignore the “increase your cadence” in workouts.
SPEED - FULL CONFESSION, I am cheating by 2.088% on my speed. 2% on my current max of 50.8 mph, or average of 14.728 mph, I don’t care, all you level 6’s can eat your heart out. Does a level 25 care that I merely reached 49.377 mph max speed?.
Future Plans. “NO”, I will not adjust my spreadsheet to account for the speed difference, even if this is easy. . And “YES” I may add a second device for cadence. A Xmas present may be in the works for an HR arm or wrist monitor, which is also important to me. Who knows, I may even get a fat tire bike for the trails outside my house and switch from lap swimming year round to year round biking…
Hope this helps other nerds. My first post.