Originally Posted by Shiznaz
It looks like a pretty big cog in the back though, at least 20 or 22 so the gearing isn't that insane. They used to make really big chainwheels with upwards of 100 teeth or more, but they were usually mated to other pretty big cogs.
My weekend ride is pushing 50x20 which comes to around 65in, the chainring is nowhere near as big as that one. That bike has got to be pushing at least 90in.!