Bicycle Power Calculator (metric)
Assumptions:
Constant speed analysis
Drag coefficients reference "Science of Cycling", E.R. Burke, Leisure Press, 1986, pg 126.
Inputs
Wheel Diameter (cm) Crank Length (cm)
Bicycle Weight (kg) Gear Ratio (#Teeth Rear/Front)
Desired Constant Speed (kph) % Grade (+ for uphill,- for downhill)
Rider's Weight (kg)
Air Resistance Coefficient (m^2) = Cd*FrontalArea Rolling Resistance Coefficient (dimensionless)
Mechanical Losses (3-5% is typical) %
Calculated Outputs
Total input power from the rider Watts Hp
Power to overcome air resistance Watts %
Power to overcome rolling Watts %
Power needed for elevation change Watts %
Power lost to friction, etc. Watts %
Energy to wheels per km kJ Human Energy per km (28% eff) Cal
Average Ground force Newtons Pedal Speed (crank rate) RPM
Average Pedal force Newtons Speed m/s Tire RPM RPM
copyright 1999 Penn State      19 August 2005 by John S. Lamancusa - Penn State University (jsl3@psu.edu)
Accuracy checked by ME288 Product Dissection class, Underlying Equations
Modified to work with Netscape 4.0 by Matt Lindenberg

Product Dissection Homepage

Modified to metric system for use in Physics of Electric Vehicles in November 2009. All created errors are the responsibility of
Bruce Emerson. Please send any corrections or comments to Bruce. My personal thanks to John Lamancusa
for the original work which stimulate these efforts on my part.