Originally Posted by
Lycosa
...magical point of being warmed up and literally believe you could ride on forever? Man I love that feeling.
+ 1 to that.
I'd say that when you can do back-to-back 50 milers and not feel discomfort, during and after, then you're ready for your century ride. You sound determined and that probably counts the most, but there is no sense in torturing yourself. Enjoy the ride!