
Science of Cycling: Aerodynamics & Wind Resistance
Aerodynamics Page: 1 of 2 Every bicyclist has to overcome wind
Aerodynamics Page: 1 of 2 |
Every bicyclist has to overcome wind resistance. Most recreational
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Wind Resistance Every cyclist who has ever pedaled into a stiff headwind knows about wind
Aerodynamic drag consists of two forces: air pressure drag
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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 felt when pedaling. The only greater obstacle is climbing up a hill: the effort needed to pedal a bike uphill against the force of gravity far outweighs the effect of wind resistance. |
Calculate the Aerodynamic Drag and Propulsive Power of a Bicyclist | |
Fill in the information in the boxes.
Velocity is your velocity (mi/hr) as read on a speedometer.
Wind velocity (mi/hr) is – (minus) if it is a tailwind, + (plus) if it
Weight is in pounds.
Grade is the angle of the slope. 0 is flat, 90 is a vertical wall.
Click on the “Calculate” button.
Notice the drag force and power required to keep you moving at a constant
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This calculation requires a JavaScript-capable browser. |
Notes on the calculator: Please be aware that we’ve made some assumptions in order to simplify this calculation. For instance, this calculator does not take into account the body position (or size) of the rider in regard to wind resistance. In addition, other factors, such as the coefficient of friction are fixed. Also, if you put in “unrealistic” figures you will get unrealistic results. Finally, please be aware that the “Calories per minute” figure is assuming that the human body is 100 percent efficient–this is not the case (20 percent efficiency is closer). For a more accurate figure try multiplying the “Calories per minute” by a factor of five. |
Reducing resistance
Frame builders and designers have been working on creating
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While improvements to frames and components have improved aerodynamic performance, the cyclist is the largest obstacle to dramatic improvement. The human body is not very streamlined. Body positioning is important; road cyclists use “drop bars” to allow themselves to reduce their frontal area, which helps reduce the amount of resistance they must overcome. Reducing the frontal area helps riders increase their speed and their efficiency over time. In addition to positioning, small details like clothing can also make a big difference in reducing “skin friction.” Tight-fitting synthetic clothing is worn by almost every professional rider, both road and mountain. Many recreational riders are also wearing bicycle clothes for the improvement in aerodynamics as well as comfort. |
Aerodymanics Page: 1 of 2 |
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