骑行功率转速度计算器

计算原理

The tool inverts the standard cycling power equation. Power at the pedals is (Crr·m·g·v + ½·ρ·CdA·(v+wind)²·v + m·g·sin(atan(grade/100))·v) ÷ 0.95, with air density ρ = 1.225 kg/m³, gravity g = 9.8067 m/s² and a 0.95 drivetrain efficiency. That cannot be rearranged for v algebraically, so it runs sixty rounds of binary search between −20 and 30 m/s to find the speed your wattage actually produces.

Surface / bike sets the aerodynamic and rolling constants together: Road bike CdA 0.32 and Crr 0.005, TT bike 0.24 / 0.004, Gravel 0.36 / 0.012, MTB 0.42 / 0.020, Commuter 0.45 / 0.008. On the flat CdA dominates — at the default 75 kg rider, 8 kg bike and 200 W the breakdown shows aerodynamic drag taking about 80% of your power. Tilt the Gradient field to 5% and gravity takes 85% instead.

Fixed CdA presets are the weak point. Your real frontal area swings enormously between hoods, drops and a tuck, and 0.32 describes a moderately aggressive road position rather than any specific rider, with no field to enter a measured value. Air density is pinned at sea level, so mountain speeds read low. Wind is a pure head- or tailwind with no crosswind or yaw angle, and drafting is not modelled at all.

常见问题