Originally Posted by jimmuller

Riding 100mi isn't so very different from riding 100km. Really. The trick is knowing how much and what to eat and drink. Hint: Lots and often, but not junk food. You must maintain your blood sugar. You must be comfortable on the bike. You must pace yourself instead of racing off too hard early. If you can do this for 50mi or 100km or whatever, you can do it indefinitely.

For me the prime challenge is that my knees will eventually get sore if I push too hard. At the end of really long day that's what I feel most. Base miles help spve this. Otherwise, just stay in shape and experiment with your replenishing until you find what works.