Energy consumption during cycling
Speed km/hr
Cycling time t min
Weight of cyclist kg
Weight of the bicycle kg
Rolling resistance coefficient Cr -
Air resistance coefficient Cw -
Frontal surface area Af m2
Uphill slope k %

Cw·Af m2
Air resistance Fair = ½ ρ v2 Cw Af N
Rolling resistance Frol = mtot g Cr N
Force for climbing Fclimb = mtot g sinφ N
Energy per minute E = Ftot v t, t=60 s kJ/min kJ/min
Energy "burned" per minute 1) kJ/min kcal/min
Efficiency of the cyclist %
Driving power P = F v W
Energy delivered E = P t kJ kcal
Energy consumed (burned) 1) kJ kcal
 1) The energy burned is approached using reference tables of different web sites like source1. Reference values are correlated to the energy delivered by cycling. 2) The dimension kcal (1 kcal=4.19 kJ) is the old dimension for Joules. 3) The energy delivered by the muscles is small compared to the energy burned, only 12.5% with a cycling speed of 20 km/h and 20% at 30 km/hr. 4) In comparison, the efficiency of a large electric powered motor is about 90%, of a diesel engine 40% and a petrol engine 25%. In the calculation of the efficiency of an electric powered motor one should consider the efficiency of power stations that transform fossil fuels in electricity. The efficiency of a coal power plant is about 40%, that of a gas power plant 45%. This actually reduces the efficiency of an electric powered motor to 0.45 0.9 = 40%, not more than that of a diesel engine.
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