I have heard about the "chung" method for using your bike on windless days as its own wind tunnel
Here is what little i know of the method:
-find a windless day
-ride a flat loop, trying to hold constant speed
-record average power and speed
-if you do this enough times, varying things like aero helmets, you can determine faster/slower helmets, etc etc
What i dont know
-i know there is some way to correct for minor variations in speed between runs to back to the CDA- how do you do this?
-what is the formula to run backwards from speed/watts to CDA? i have ron ruffs spreadsheet- but is that the correct formula?
Proud member of the Guru Cartel, EH!