I've done it - year before last, solo. About 4hrs 45min. Eat on the bike and don't stop. The course I did it on was fairly flat - the only stop I had was for about 1 min. to pee. I rode quite a bit that year including a double in 11.5 - I hope to do better this year. Also, both those rides were on a SS. Last year I did a century and it took me 12.25 hours - it was off road and included ~18 - 19K feet of climbing.