Not too far before reaching the 200-m-to-go sign, Rigoberto Urán was headed for gold -- and then looked over his left shoulder. That little hesitation by the 25-year-old Colombian was all the opening that 38-year-old Alexander Vinokourov of Kazakhstan need to slip into the gold-medal position. It was a great move by Vinokourov!
Vinokourov's gold-medal winning time was 5h 45' 57" over the 250-km (155-mile) road race, giving him an average speed of 12.04 m/s (43.36 km/hr or 26.94 mph). That's a great average speed for a distance 24 km (15 miles) longer than the longest stage in this year's Tour de France. Based on how I calculated calories burned for the Tour de France, I estimate that Vinokourov burned about 8000 Calories in the biking-only part of his effort.
I felt really bad for Fabian Cancellara of Switzerland. With just over 10 km (6.2 miles) to go, he was leading the race and heading into a tight turn to the right. He crashed to end his gold-medal dream. As he entered the turn, Cancellara was not leaning enough into the turn and, hence, was not allowing his bicycle's tires to push out to the left with enough force to allow the road to push his tires to the right. As one moves in a circle at constant speed, the inward, or centripetal, acceleration is proportional to the square of the speed and inversely proportional to the turn radius. If the inward force is not large enough for a given speed, a larger radius is needed. That's why Cancellara crashed.