I don’t know my CdA, what do I do?

To ballpark a CdA…

I know my average power: Go to a course where the average power is known. Enter into your forecast the average power for your ride. Adjust the CdA to reflect the average speed you attained for this power. A lower CdA will increase your average speed and a higher with decrease average speed. Tip: If you have Premium access enter into the Date Picker the time you attained the average speed at wattage on the course.

Without power:

TT Bike in Skinsuit Aerohelmet: 0.19 – 0.22

Road bike drops: 0.28-0.32

Road bike hoods 0.32-0.36

Standing: 0.4<

Author: Ben Norbury

Ben Norbury is four times Manchester & District Middle Distance and Best All Rounder Time Trial Champion from 2016-2019. During this time he developed software to eliminate uncertainty of the weather conditions out of his pre-race preparation.