Analytic Cycling Logo Gear Selection, Pursuit

Your training has been going well.  You plan to do a pursuit today.  Yesterday you did a pursuit at 12.5 m/s at a cadence of 112 with an air density of  1.20 kg/m3.  Today you think you can do as well, but the air density is 1.29 kg/m3.  Yesterday's data:

 
Recommended Gear
Closest Gear  51x16    
Gear Inch, Closest  84.2  inch 
Rollout, Closest  6.719  m 
Maximum Speed  12.5  m/s 
Wheel Diameter  671  mm 
Desired Gear Inch  83.9  inch 
Desired Rollout  6.696  m 
Frontal Area  0.5  m2 
Coefficient Wind Drag  0.5  dimensionless 
Air Density  1.2  kg/m3 
Weight  75.  kg 
Coefficient of Rolling  0.004  dimensionless 
Effective Stroke  70.  degree 
Grade  0.  decimal 
Wind Resistance  23.4  kg m/s2 
Rolling Resistance  2.9  kg m/s2 
Slope Force  0.0  kg m/s2 
Crank Length  165.  mm 
Maximum Cadence  112.  rev/min 
Pedal Speed  1.9  m/s 
Average Pedal Force  170.  kg m/s2 
Effective Pedal Force  438.  kg m/s2 
Power  330.  watts 

Notice that Power was 330 watts yesterday.  For the same watts today, under today's conditions, you can estimate your speed using Speed, Given Power which estimates speed today at 12.22 m/s.   

Speed For Given Power 
Speed For These Parameters  12.22  m/s 
Power  330  watts 
Frontal Area  0.5  m2 
Coefficient Wind Drag  0.5  Dimensionless 
Air Density  1.29  kg/m3 
Weight Rider & Bike  75  kg 
Coefficient of Rolling  0.004  Dimensionless 
Slope of Hill  0.  decimal 

Today's suggested gear selection, based on yesterday's power output and today's Air Density, is one gear lower, a 50x16 instead  of yesterday's 51x16.

Recommended Gear
Closest Gear  50x16    
Gear Inch, Closest  82.6  inch 
Rollout, Closest  6.588  m 
Maximum Speed  12.22  m/s 
Wheel Diameter  671  mm 
Desired Gear Inch  82.0  inch 
Desired Rollout  6.546  m 
Frontal Area  0.5  m2 
Coefficient Wind Drag  0.5  dimensionless 
Air Density  1.29  kg/m3 
Weight  75.  kg 
Coefficient of Rolling  0.004  dimensionless 
Effective Stroke  70.  degree 
Grade  0.  decimal 
Wind Resistance  24.1  kg m/s2 
Rolling Resistance  2.9  kg m/s2 
Slope Force  0.0  kg m/s2 
Crank Length  165.  mm 
Maximum Cadence  112.  rev/min 
Pedal Speed  1.9  m/s 
Average Pedal Force  171.  kg m/s2 
Effective Pedal Force  439.  kg m/s2 
Power  330.  watts 
 

©1997 Tom Compton