Originally Posted by
mcours2006
One of our stronger riders always posts using this kind of designation. Problem is that his zone 2 is zone 3 for a lot of people, and even zone 4. And his zones have changed in the last few months as he's gotten stronger.
Thats why you add the speed. If you know you are not in zone 2 at 20mph on flat ground, that ride is going to be too hard for you.