Useless hindsite! This is where a heart monitor could have been a very big asset. They are the perfect tool to tell you that you are starting off too fast. If your lowest gear puts you "in the red" on that early hill, you gotta walk if you still want to be going 50 miles later.

Of course, you have to do some homework ahead of time so you know what your top heart rate is and your zones.

Years ago I did a century with a mountain pass as the big hill but there were some tough ones well before. I wore the monitor and limited myself to a painfully low HR for the early ones and let many riders go. (I'm a light, skinny climber. Letting guys I can climb with go hurts!) But later, I got to climb that long pass up a historic wagon route at 10 points higher HR and fully enjoy it. Spent the late miles passing gassed riders I had let go hours earlier.