("beta") Inclination angle, = arctan(grade/100) Height above sea level (influences air density)Īir temperature, in ° Kelvin (influences air density) Rolling friction including the dynamic (speed-dependent) rolling friction, air drag including the influence of wind speed, mechanical losses, and uphill/downhill forces. The following equations take into account all of the relevant resistance components: The most essential of the equations the Speed&Power Calculator is based on: TopOfPage | Speed&Power | BodyMassIndex-Calculator | Text | Formulae Most of the data and assumptions used for the calculator are based on (and match well with) frontal area measurements, and, first of all, measurements done with SRM Power Measuring cranks.
On a smooth velodrome surface, rolling resistances may be essentially lower.Ĭonsider this also for the values that this calculator delivers for the Superman Position. The applied rolling resistances refer to asphalt road pavement. The air drag share of the bicycles themselves is taken into account too.Īt low speeds a wider tire (less rolling friction) may be advantageous while, with higher velocity, a narrower one (less air resistance) increasingly gets the upper hand. Smaller front wheels of recumbents generate more rolling friction but less air resistance.
The front wheel has more share in the air drag than the rear wheel. Tire thread induces air vortices and thus speed-dependent additional resistance. (not true with the streamliners White Hawk and Quest whose fairings enclose the wheels almost entirely).Ī thicker tire wall (touring tire) tends to generate higher rolling friction. The calculation also regards the following influences:Īt wider tire tends to generate less rolling friction but more air resistance The rolling frictions of the front and rear wheel tires each are taken into account separately. Inside the fully streamlined bicycles, of course, the rider's frontal area is assumed to have no influence. These assumptions yield good matches with frontal area measurements, and with measurements done with SRM Power Measuring cranks. The rider's frontal area is evaluated approximately from the rider's body height and weight,Īnd a parameter which depends on the selected kind of bicycle ( see FAQ). The amount of Calories Burnt by the Rider = kcal (assumed efficiency: 22 percent) will be calculated.īesides, the program will evaluate the variable whose fields are empty (Trip Distance or Trip Duration, respectively).įor coast-down simulations, set the Power value to zero and the Slope to the desired negative value.įAQ TopOfPage | Speed&Power | BodyMassIndex-Calculator | Text | Formulae In case you enter (before clicking the "Calculate"-Button): Your browser doesn't support JavaScript, or JavaScript has been disabled.įurther results: Effective Drag Area C d*A Rolling Resistance Coeff. With both fields filled, the variable evaluated previously will be calculated again (facilitates quick comparisons). The input field of the variable to be calculated must be empty. Headwind positive, tailwind negative values Uphill positive, downhill negative values Bicycle Speed (Velocity) & Power Calculator: Recumbents, recumbent bicycles, racing bicycles, normal bicycles, aerodynamics, air drag, rolling friction, uphill power.
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