"I checked the Delorme 5.0 software for the grade of Harlem hill. This measure is from where the Fred Douglas Circle road intersects central park road(bottom of hill)to the top of the hill. It is a 44.9 foot vertical climb and a horizontal distance of 734.5 feet. Therefore, the grade is 6.1. Here is the calculation 44.9/734.5.

Hope this helps.

Bob

Definition (not mine) of Grade is below:

Grade -- steepness of hill
Most of us find that climbing up a 200-foot hill which is steep takes more out of us than a 200-foot hill which is gentle. A simple and very useful measure of steepness is ""grade"":

grade = vertical_climb / horizontal_distance

where both vertical_climb and horizontal_distance are both converted to the same measurement units. So if a hill goes up 264 feet in 2 miles, then we can first convert 2 miles to 10560 feet -- so the grade is then 0.025 = 264 feet / 10560 feet, which is 2.5%.

What does this ""grade"" number mean?


0% grade is exactly flat (and a negative grade, less then zero, is downhill).
2% grade does not seem very steep, but it's enough to substantially reduce forward speed, and for most riders it will absorb more than half their power output.
6% grade is enough to cut speed to well under half, and absorb more than 80% of a rider's power output (leaving less than 20% to fight air resistance and rolling friction).
10% grade, and anyone who is not a fit and frequent rider is off their bike walking -- and anyone who is not a racer is reaching for all the extra power they've got.

"