Less weight going up a slope means
faster times. How much faster?
Suppose one is considering buying a new, lightweight frame
or going on a diet. What is the benefit from having less weight? How much
time would be saved over a given distance on a specified slope? How much
more distance would be covered in a given time?
Two riders, identical except that one has less weight than
the other, ride a given distance up a hill. The the calculation gives the
distance and time between the riders as the lightest rider reaches the given
distance.
The plot shows the benefit from less weight when riding
up a hill. The range of the plot is from 10% to +10% grade and from 0 to
5 kg less weight. The table gives specific values for the given speed.
Note that large changes may produce mathematical results,
but may not have realworld meaning. Keep changes small.
"Negative values for improvements" show that
weight is an advantage going down a hill. The plot shows that weight
is more of a penalty going up hill than an advantage going down.
Example:
Benefit From Less Weight
This Much Less Weight 
5 
kg 
Over This Distance 
2000 
meters 
On Hill of Slope 
0.03 
Decimal 
Faster by 
8.69 
s 
Ahead by 
64.82 
m 
Frontal Area 
0.5 
m^2 
Coefficient Wind Drag 
0.5 
Dimensionless 
Air Density 
1.226 
kg/m^3 
Weight Rider & Bike 
75 
kg 
Coefficient of Rolling 
0.004 
Dimensionless 
Power 
250 
watts 

