I bought a new Centurion bike last winter, and have been riding regularly. Decided to keep a log of my travels and hopefully chart any progress. Usually I ride down the "Fujisawa Yamato Jitenshado (cycling road)" to Enoshima, round to Kamakura and back home via Ofuna. It's a good trip for me, at about 35 km depending on which route I take.
When I look at the average times of the Tour de France riders, I am humbled. They are incredible athletes, averaging something like 38 to 40 kph on the stages. Lance Armstrong averaged something like 40-plus kph over a whole tour, which means he was probably doing 30 uphill and 60 down. Wow!