Originally Posted by unterhausen

My previous answer was true for me, and since I ride longer distances I have to worry about how it affects me. I'm not going to go out and do a 300 or 400km ride for training, doesn't make sense to me. 20-35 miles is plenty for most of us. If a ride is much longer than that, quality is going to suffer. Before my first 1200km ride, I mostly did 20 mile training rides during the last 2 months and concentrated on getting faster. That was after a base of plenty of longer rides. There is something to be said for keeping fresh, and after you get a base, you aren't going to stay fresh by slogging through long rides.

I like to say anyone can ride 400km. However, on a less than stellar ride, I have taken almost the full randonneuring time limit, which is 27 hours. One such ride, I one-legged it for the final 20 miles because my knee hurt. Not recommended, but I'm not going to quit with that small of a distance remaining.