CdA is the product of drag coefficient (Cd) and frontal area (A), measured in m². It represents your total aerodynamic drag. Lower CdA means less air resistance. Typical values: hoods 0.35–0.40, drops 0.30–0.35, TT position 0.22–0.28 m².

How much time does 0.01 m² CdA save?

On a flat 40 km time trial held at around 40 km/h, reducing CdA by 0.01 m² saves roughly 25 to 35 seconds, depending on your power and speed. The savings grow at higher speeds because aerodynamic power demand rises with the cube of velocity.

What are the easiest aero gains?

In order of impact: rider position (biggest gain), skinsuit vs loose clothing, aero helmet, shoe covers, deep section wheels, and aero frame. Position changes alone can reduce CdA by 0.05–0.10 m².

Is aero more important than weight?

On flat to rolling courses, aerodynamics dominates. At 40 km/h, roughly 80% of resistance is aerodynamic drag. Weight only matters significantly on steep climbs (above 5–6% gradient). For time trials, aero is almost always more important.

Aero Savings Calculator — Free Performance Tool

Aero Savings Calculator

Calculate time and power savings from aerodynamic improvements.

Baseline CdA

Current position CdA

Improved CdA

Target position CdA

Course Distance

Length of the course or TT (e.g. 40 km)

Average Power

Power output in watts

Rider + Bike Weight

Combined rider + bike + kit mass

How We Calculate This

Power-Speed Equation

Speed is solved iteratively from: P = 0.5 x ρ x CdA x v³ + Crr x m x g x v

Time saved = (Distance / Baseline speed) - (Distance / Improved speed)
Watts saved at same speed = 0.5 x ρ x (CdA₁ - CdA₂) x v³

This assumes flat terrain and zero wind. Your entered power is treated as power at the wheel (drivetrain losses of roughly 2 to 3% are not subtracted), and since the same power applies to both positions, the time and watt savings are unaffected. Real-world savings vary with course profile and conditions.

Frequently Asked Questions

Last updated: 2026-03-03

All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.

Aero Savings Calculator

How We Calculate This

Power-Speed Equation

Frequently Asked Questions

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