Methodology
How WattGap calculates your CdA
Reference figure first, then size, fit and position, then your rides.
Start from a measured baseline
Every estimate starts from a published wind-tunnel figure for your bike — never a blank guess. This gives a sensible number from day one.
Layered adjustments
On top of the baseline WattGap applies frame-size scaling, a fit adjustment derived from your body proportions and cockpit, and optional position-analysis changes.
Learning from rides
Qualifying rides produce a measured CdA by solving the power equation for drag. After 10 rides that figure blends in, capped at 20%, so the model improves without becoming noisy.
Try it on your own rides
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