When Miguel Indurain announced to attack the hour record, the magazines predicted a sensational mark of 55 or 56 km/h. But some experts were more cautious, because Indurain’s aerodynamic position on the bike was very poor – his head is very high in the air, always well above his shoulders.
But in the road time-trials this did not seem to slow him down very much…
The actual attempt was finally well below 55 or 56 km/h. He started very slow and needed 20 km to match up with Graeme Obree’s split times. After reaching an average speed of 53 km/h, he slowed down again and needed a sudden outburst between 30 and 35 km to stay above 53 km/h. He used a Pinarello carbon bike with a very aerodynamic frame and Campagnolo disc wheels.
As stated in an article on „53×12.com“ by Dr. Michele Ferrari , it is likely that Indurain, only 5 weeks after the finish of the Tour de France, was not at his peak form when he set his record. He also points out that Indurain’s position on the bike didn’t seem to be optimal (however, as I mentioned above, it was good enough to win all the major time trials on the road…) A key factor could be that the rider’s track speed is not constant, presenting continued accelerations and decelerations corresponding to curves and straight-aways. A heavy rider pays dearly for these accelerations—far more than a light-weight. Finally, at these speeds the one-hour record, Indurain clearly suffered more from the centrifugal force in the curves, since he is about 15 kg heavier than the „normal“ cyclist. (Note that Ondrej Sosenka (2 meters tall!) chose the track in Moscow (for his UCI hour record 2005) which has a length of 333 m,and therefore less centrifugal forces…)