This program is free and allows you to enter in your weight, bike
weight and other info about your bike and your power output. You must
also enter course data such as road conditions, wind and the position of any
major grade changes. The grade changes can be gotten from contour maps
or an altitude sensor like theS710 or xtrainer plus.
The program uses finite element analysis to update your speed and distance
traveled and has the ability to estimate the proper power output based on
the course. For example, you won't pedal down a hill as hard as you
pedal up a hill.