Originally Posted by BlazingPedals

Southern Michigan averages 15-20 feet per mile. A 1500-foot century isn't unheard-of. The last time I did the Wolverine 200, it consisted of 40 laps of Bell Isle, with at most 5 ft/lap of climbing. Over 200 miles, that made for 200 feet total.

Originally Posted by Jim from Boston

My first century, actually a double, was in 1971. The Wolverine Sports Club puts on an annual double century on Belle Isle, an island park in the Detroit River with a five mile perimeter, so the 24 hour double century is 40 laps. It’s totally flat and you are obviously always in the company of lots of other cyclists.

As I recall, at that time at least, it was the only time camping was allowed on the island so it was a festive affair. My roommate and I decided to do it, with no training, and me on my Schwinn Suburban and he on his Varsity.