Originally Posted by
sp00ki
the problem isn't the distance, or even the tempo, it's the grades. the only thing separating doing 100 miles on a fg and doing it on a geared bike is the hills. once they start turning into mountains, you should reconsider.
+1
It's the hills that will test you. If your gearing is low, climbing is easier but the descent won't be as fun. If your gearing is high, well, the climb becomes more challenging.
That said, I've ridden my singlespeed a little over 80 miles on a recent ride. It's not uncommon to hear of century rides on a FG/SS.