Let's not forget listmember Jan Heine's incredible achievement last summer in Paris Brest Paris. That event is absolutely NOT a race but many riders see it as an opportunity to set personal best times. Riding a 1948 Rene Herse tandem, outfitted with much (or most?) of the period correct equipment, Jan and his female stoker finished in 52:44, covering the 765 miles at an average speed of 14.5 mph, if memory serves. I believe he did it unsupported and was the first mixed tandem finisher, and second to all tandems. Obviously, it's not about the bike, but my guess is in this case the bike didn't hurt.