From the MIT Center for Sports Innovation and Technology

An interesting article from Bicycling magazine, September 2006, p. 32. Great insights into bicycling aerodynamics and the science of cycling.
1. Time trialing is about efficiency, not power. It’s much easier to increase efficiency rather than increasing power.
2. Your bike accounts for only 15-20% of overall drag.
3. 75% of drag is determined by your body’s resistance against the air.
4. There is a relationship between biomechanics and power output and aerodynamics. You have to balance all 3 to maximize power output over time.
5. A non-aero helmet creates four times the drag of a non-aero wheelset. So spend money on an aero helmet!
6. How the race number is fixed to the bike matters – make it as flat as possible against the bike.
7. On a round tubed bike frame, a water bottle on the seat tube is more aero than without. It is more aero to put it there than putting it on the down tube.
8. Wearing gloves creates more drag than having a non-aero front wheel.