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Aero Savings Calculator
Calculate time and power savings from aerodynamic improvements.
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
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.
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.
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.
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.
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Last updated: June 2026
All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.