CYCLELAB 360
Cycle Lab
Via Pilastri 4
05100 Terni
info@cyclelab360.com
SPEED FROM POWER
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!
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Speed
(km/h)
-
Seconds per km
NaN s/km -
Rider power/weight ratio
4.29 W/kg -
Power to CdA ratio
Infinity W/m^2
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.
