Originally Posted by
I-Like-To-Bike
47% grade in NJ? Not likely unless a novel method of measuring grade is used.
The normal way to calculate elevation grade is: grade = elevation/ distance x 100. Elevation is the height measured from lowest point to the highest point. Distance is is horizontal distance from the bottom point to the highest point.
Take a look at the areas of western NJ on a topo map. Start around Round Valley. Its not all flat in NJ.
Originally Posted by
DogBoy
Just so we are clear: Grade = elevation/distance. So 47% grade means that there is a 47 ft increase in vertical elevation for every 100 ft of horizontal travel. A 47% grade will produce an angle of 25.2 degrees above horizontal. %Grade != Angle degrees. 47% grade on a bike? I'd say doable, extremely unpleasant. 47 degree angle on a bike? I'd say not doable without special accomodations.
And as you mentioned, its elevation over distance, but its not restricted to 100 ft - just rise in elevation over a distance. Which is why you even see the mention of 37% (20 degrees-ish?) grade over a 6.5m distance in the Canton Ave article on wikipedia.