“Every cyclist who has ever pedaled into a stiff headwind know about wind resistance. In order to move forward, the cyclist must push through air. This takes energy. Aerodynamic efficiency – streamlined shape that cuts through the air more smoothly – enables a cyclist to travel much faster, with less effort. But the faster the cyclist goes, the more wind resistance he experiences, and the more energy he must exert.”

“Aerodynamic drag consists of two forces: air pressure drag and direct friction. A blunt, irregular object disturbs the air flowing around it, forcing the air to separate from the object’s surface. The low pressure region behind the object results in a pressure drag against the object. With high pressure in the front and low pressure behind, the cyclist is literally being pulled backwards. Streamlined designs helps the air close more smoothly around bodies and reduces pressure drag. Direct friction occurs when wind comes into contact with the outer surface of the rider and the bicycle. Direction friction is less of a factor than air pressure drag.”

“On a flat road, aerodynamic drag is by far the greatest barrier to a cyclist’s speed,  accounting for 70 to 90 percent of the resistance. The only greater obstacle is climbing up a hill.”

Aerodynamic performance has improved with better equipment, but the cyclist remains the largest obstacle to reducing drag and direction friction. The human body is not very aerodynamic. Body position is critical for reducing frontal area and thus reducing direction friction and drag. Improved body position provides increased speed and efficiency. Road cyclists use aero bars to improve position. The position may be further improved with the addition of the VeloView Prism.

Reference:

Exploratorium

https://www.exploratorium.edu/cycling/aerodynamics1.html