Whatever bike you ride, be sure that you:
- drink lots
- eat lots (even if you don't feel hungry)

If you don't, you'll bonk somewhere past the 70-mile mark. It's like the 20-mile "wall" in marathons.

And don't blast out the first 10 miles because you're excited to be in a century. Ease into it, and you'll be fine.

Hope this helps.