Cycling calculator: speed from power

Use the sliders to adjust the various inputs to calculate the speed sustainable for a given power. 

Not sure what values to use for various input factors? I've included a few thoughts and guidelines on each below the calculator. Of course having your CdA measured at an Aerocoach session would be a great start!

CdA and Crr

CdA
(m2)
Examples Crr Examples
0.17 - 0.20 Very aero time trial riders 0.0020 - 0.0026 Indoor wooden track
0.20 - 0.25 Time trial set ups 0.0030 - 0.0040 Smooth concrete track
0.22 - 0.28 Ironman set ups 0.0040 - 0.0045 Good quality bitumen with race tyres
0.25 - 0.30 Road race bike in aero tuck 0.0045 - 0.0060 Rougher bitumen / chip seal
0.30 - 0.40 Road race bike in upright positions

AIR DENSITY

Air density is not always obvious and so that's why we've created this air density calculator to make it easy! 

Drivetrain efficiency

Drivetrain efficiency of well maintained bicycles is typically around 97-98%.

Wind

Wind measurements are obviously tricky as they are affected by various factors including the direction of wind relative to the rider's direction. Wind speed at rider level will typically be around half that reported by the weather bureau/station. This is because standard weather station wind measurements are made at a height of 10m above ground and wind speed reduces closer to the ground boundary layer. Naturally the wind speed and direction at any moment is also impacted by trees, buildings, vehicles and other features.