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The PBscience team recently contributed to the book Performance Cycling: the Science of Success, edited by Dr James Hopker and Dr Simon Jobson. Dan and Helen co-authored a chapter entitled Training with heart rate and power while Helen also contributed a chapter on Coach-athlete relationships. If you want to learn more about the PBscience coaching philosophy this is a good place to start.

Critical Power Calculator

Assumptions:
Constant speed analysis
Bike weight = 22 lb
Drag coefficients reference "Science of Cycling", E.R. Burke, Leisure Press, 1986, pg 126.


Inputs
Wheel Diameter (inches)         Crank Length (inches)
Desired Constant Speed (mph)       Rider's Weight (lbs)
% Grade (+ for uphill,- for downhill)       Mechanical Losses (3-5% is typical) %
Gear Ratio (#Teeth Rear/Front)            
Air Resistance Coefficient (lbf*s^2/ft^2)
Rolling Resistance Coefficient (lbf/lbf)       


Calculated Outputs
Total required input power from the rider       HP     Watts
Power needed to overcome air resistance      HP   %
Power to overcome rolling resistance in tires  HP   %
Power needed for elevation change               HP   %
Power lost to mechanical losses, friction, etc. HP   %
    Calories burned per mile kcals
    Average Pedal Force Lbs     Average Traction Force Lbs
    Pedal Speed RPM                Tire Speed RPM


Acknowledgements

These materials are based upon a course presented by the University of Washington developed under the Manufacturing and Engineering Education Partnership.  The intent of this partnership is to develop new educational programs and to facilitate the free dissemination of these materials, thereby saving other institutions the expense and time of similar developments.  Accordingly, all materials for this course may be freely copied and edited as desired.