100 miles along county roads. I live in Wisconsin and I will ride out from Madison Northward or westward along roads. Right now a century takes me around 8 hrs or so(when I know the route well and am not looking for directions all the time). Topography is about what you expect for country roads. No massive climbs but some rolling hills. Downtown Madison seems to be a low point and you'll gain about 1000+ feet or so overall for a 50 mile ride and then go down about 1000 ft on the way back. There are obviously some climbs and downhills. I can hit at about 12-13 mph on this kind of stuff. On flat dirt trial(like military ridge) which is mostly flat, I can get about 15mph or a little better. For the dirt trails I usually ride my 1999 Schwinn passage and for county road trails, I ride my 2011 GT 5 series(both bikes with stock parts except for saddle and the 28 inch wheels I put on the Schwinn for trails.) How about you guys. I haven't found any completely flat routes to test my speed on flat. I'm amazed that Cat 4 races average 24-25 mph. I'm assuming most of those courses are paved and pretty flat, right?