Originally Posted by
bikerjp
How did you calculate the average speed? Miles per hour is a distance divided by time function and there isn't any time or distance in your numbers.
I hypothesized about a 180 pound rider with 20 pounds of bike/water/shoes/spare tube/etc which is about 90kg riding on the brake hoods with .4 meters^2 Sd and .760 Cd per Grassi and Gibertini's measurements with Crr of .004 and assumed symmetrical hills.
200 Watts is a reasonable power output most male cyclists should be able to manage. I assumed it for up-hill and down-hill until I got to the 12% grade at which point I figured the cyclist would be spun-out and no longer pedaling.
Distance/speed = time
Distance/time = speed
(1 mile up + 1 mile down) / ( (1 mile up) / (miles/hour up) + (1 mile down) / (miles/hour down))
You could use any other distance and it would work out the same.