Originally Posted by Gonzo Bob
I once looked at this using analyticcycling.com. I calculated "time up a mountain" using various grades and found that grades between 8-10% give the fastest times - thus the fastest climb rates. This, however, was just a theoretical exercise. I don't know if it pans out in the real world.
I'll bet you are right about the existance of a peak climb rate verses % grade. I don't know what the number is and I would think it might vary a little with power to weight ratio, but not as much as the actual rate would vary.
Joe