It's a great debate: miles vs. hours. I'm a slow rider, but I stick with it and over time the miles add up. Here's a question, though: If it takes me 7 hours to complete a century and it takes you 5 (same route), then how do you evaluate our relative performance with only one set of data, i.e., miles or hours? Seems to me you need to consider them together to get the complete picture. Obviously, you're the stronger rider, but I spent more time on the bike.