WANNABEE KING OF THE MOUNTAIN WATTS
Gravity Watts
The formula for Gravity is: Watts_to_overcome_gravity = 9.81 x P x %slope x V. Where Cslope is a coefficient, P is your weight, and V is your speed on the road. The faster you go, the more you weigh, and the steeper the slope, the more power is required to take you up the hill.
Friction Watts
The formula for Friction is: Watts_to_overcome_friction = 0.1 x V x P
When the velocity V is measured in meters/second and the weight P is measured in kilos, for a decent quality bike, with well-inflated racing tires on a smooth road, the metric Cfriction is said to be about 0.1.
When the velocity V is measured in meters/second and the weight P is measured in kilos, for a decent quality bike, with well-inflated racing tires on a smooth road, the metric Cfriction is said to be about 0.1.
Wind Resistence Watts
The formula for Wind Resistance is: W_to_overcome_air_resistance = Cair x (V + Vwind)^2 x V. If there is no wind, it is simply: Cair x V^3.
For the metric system, Cair ranges from perhaps 0.8 for a city bike without baggage or a hybrid with baggage, to .7 for a mountain bike or loaded touring bike to perhaps 0.45 for a hybrid or upper position on a racing bicycle without baggage, to as low as 0.36 for full racing position on a conventional racing bike.
For the metric system, Cair ranges from perhaps 0.8 for a city bike without baggage or a hybrid with baggage, to .7 for a mountain bike or loaded touring bike to perhaps 0.45 for a hybrid or upper position on a racing bicycle without baggage, to as low as 0.36 for full racing position on a conventional racing bike.
Overall Watts Formula
Wrider = Cfriction x V x P + Cair x (V + Vwind)^2 x V+ Cslope x P x Slope% x V + acceleration
More details on http://www.mayq.com/Best_european_trips/Cycling_speed_math.htm
