Human Powered Vehicle Speed Simulator
Human Powered Vehicle Graphical Speed Simulator V1.1
By Warren Beauchamp
General Settings
Units currently set to English
Bike Weight in pounds
Rider Weight in pounds
  
 
Unfaired Bike CDA Calculator
Bike Type
Tire Type
Seat Angle
Rider Height in inches
CdA is 0.157
 
HPV Speed Simulator
Rider power in watts
Slope in percent
Simulation Time in seconds
Wheel Weight in pounds
Crr - Rolling resistance
CdA - Coefficient of Drag in M2
Air Temp in degrees F
Height above sea level in feet
 Show speeds > 100 MPH
 
CdA and Crr look-up table     Notes

 

Crr and CdA look-up values: *
Tires Crr - Rolling Resistance
touring tire 0.0075
406mm Conti GP 0.0072
406mm Tioga Comp Pool 0.0071
narrow racing tire 0.006
semi-wide high-pressure slick 0.0055
700C Conti GP 3000 Silica 0.0055
wide hp slick 0.005
406mm Schwalbe Stelvio 0.0045
Rinkowsky 0.003
Michelin Ecorun 0.0028
Vehicle CdA Values Bike+Rider
in kilos
Barracuda  0.055 106
Gold Rush 0.0465 80
White Hawk 0.031  
Cuda-W 0.030 81
Bean II 0.0289 98
Cutting Edge 0.0286 96
Cheetah 0.0278 93
M5 #8 fairing 0.0255  
Varna Diablo 0.02 100
Virtual Edge 0.011  
DF Standard bike 0.68  
DF Mountain bike 0.50  
DF Racing bike (hands on top of bars) 0.51  
DF Racing bike (racing position) 0.38  
DF Racing bike (using aerobars & disk wheels) 0.23  
Easy Racer (no fairing) 0.27  

Notes:

  • Calculated bike CdA varies with bike type, tire type, rider weight, and rider height.
  • All Bike CdAs assume use of a rear wheel disk.
  • Crr values should be an average of front and rear tire Crr values.
  • A negative slope is downhill (example: Battle Mountain run is -0.06% or -1.19 degrees)
  • Note that the Battle Mountain course has a 5.5 mile run up, so peak velocities at distances over 5.5 miles are unattainable.
  • Wheel weight is total rotational mass, typically around 90% of wheel weight for a spoked wheel and nearer to 75% for a disk wheel.
  • Bike weight is total vehicle weight including wheels.
  • * Crr and CdA values were gathered from a variety of locations, and some values may be only rough estimations.
  • A value of "0" may be used for power with a negative slope to simulate "coast down" testing.

Credits:
This web page would not have been possible without the help of Gerrit Govaerts. Gerrit worked with Walter Zorn to create this Excel spreadsheet from which the equations used in the calculations on this page were taken, and was instrumental in my understanding them enough to create this page. Check out Walter Zorn's web site for more HPV simulation tools.
Disclaimer:
Gerrit notes "I firmly believe that sometimes an inacurate (and that will always be the case to some extent) math model is better than none at all, but I also understand that it can easily be abused if stretched beyond it's validity. You are all advised to use it wisely and interpret the results!"
Update history:
03/12/02 - V1.0 - V1.04 Tweaked user interface and added features.
03/29/02 - V1.05 Updated to use Java based plotting util.
04/07/02 - V1.1 Updataed calculations based on feedback from Charlie Ollinger, and Gerrit Govaerts updated simulation spreadsheet. It now takes a bit longer to get to terminal velocity.
 

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