what is used for research level power accuracy?

[rons]

I have been looking at this bike power thing for a while and to date the most likely item I have seen for " accurate" power is something like he velotron. Regardless of the methods I have seen all measures may be precise but accuracy is quite another thing. For training oneself precision is way more important than accuracy. You want to know that what ever number you get is very reproducible only when comparing one person to another does accuracy really come into play. So I suspect the Newton has pretty go precision of measurement and that makes me happy. So if the true engineer/ physicists on here were to look to find the truly accurate measure of cycling power where would you look? In lab environment it would likely be a stationary device, but what about a field device? Ultimately if we knew the limits of accuracy then all of this tooing and froeing about minor tweaks to Cda, Crr etc would fall to the side. Also since the iBike uses a lot of mathematics to get the answer we read on the display there are factors in that equation that have very minor influence and others that have major influence. I would be interested in knowing the mathematical factors (not the equation) that we have access to for calibration that have the greatest influence on the number that is displayed in order of influence highest to lowest. For instance is accurate bike and rider weight > tilt calibration>> wind cal? etc

[racerfern]

Once you establish your constants of CdA and Crr, the most important variables are wind and slope which are equally important. Tilt calibration is for all intents and purposes not important since the unit figures things out itself. The only thing that could be out is the first few minutes. So that leaves wind as the absolutely most critical variable in the equation.

That's why the emphasis on doing a good wind offset just prior to doing a good cal ride to establish your wind scaling. Don't ignore things like a good tilt calibration, proper setting of weight, height, etc but "wind is thine frenemy" (for those of you who know who Robert Chung is).