Analytic Cycling Logo Downhill Sprint

When will you need the eleven?

The finish of a race is downhill.  Based on your estimate of the speed of the pack when it jumps and your Power Profile, how fast will you be going when you cross the line?  The following example shows that based on your Power Profile, you will be going about 19.2 m/s at the line, and if your jump is from 300 meters out, it will take about 16.5 seconds.  

Based on your maximum effective cadence of 110 and your highest gear of 53x12, you will be spun out long before you reach your maximum speed.  (See Gear Selection)  Buy the new nine-speed groupo and get the 53x11 you need or learn to spin at 125 cadence. 

Recommended Gear
Closest Gear  53x12    
Gear Inch, Closest  116.7  inch 
Rollout, Closest  9.310  m 
Maximum Speed  19.2  m/s 
Wheel Diameter  671  mm 
Desired Gear Inch  131.2  inch 
Desired Rollout  10.473  m 
Frontal Area  0.5  m2 
Coefficient Wind Drag  0.5  dimensionless 
Air Density  1.226  kg/m3 
Weight  75.  kg 
Coefficient of Rolling  0.004  dimensionless 
Effective Stroke  70.  degree 
Grade  -0.05  decimal 
Wind Resistance  56.5  kg m/s2 
Rolling Resistance  2.9  kg m/s2 
Slope Force  -36.8  kg m/s2 
Crank Length  170.  mm 
Maximum Cadence  110.  rev/min 
Pedal Speed  2.0  m/s 
Average Pedal Force  222.  kg m/s2 
Effective Pedal Force  571.  kg m/s2 
Power  435.  watts 

 

Sample output:  

Rider Time at 300 m = 16.5 s.

Rider Speed at 300 m = 19.2 m\s.

Plot of Speed vs. Distance
Rider Speed vs Distance

Plot of Power Profile
Plot Power Profile

 ©1997 Tom Compton