I wimped out on my ride yesterday morning (it's hot and hard to sleep), so this morning I decided to tackle the infamous "Zoo Hill", which climbs up Cougar Mountain near Issaquah.
Probably the worst hill that I've normall rode is Juanita Drive, which gains about 400' over 1.3 miles, for a 5.8% grade. I hadn't looked at the Zoo stats in a while, which turns out to be a good thing.
The climb starts immediately when you turn off of Newport, and it pretty brutal. It's more brutal if you ride for 10 minutes, look down, and then realize that you still have one gear back at the back.
I usually run out of leg strength before I run out of aerobic capacity, but I ran out of breath lots of time on the climb. Definitely a good test of my capacity.
Length: 2.63 miles
Elevation: 1200 feet
Gradient: 8.1 % average
The average gradient is misleading. There are a lot of sections that are around a 5% grade, and even a few that are flat, so that means that the steep sections are up in the 15% range.
Riding down, I had to brake most of the time, because if I didn't, I easily would have been in the mid 40's. Next time, I'll probably come down the next way.