This is one of those perennial debates that occur in the cycling world: many runners with slim builds complain that when they go down a hill next to a larger teammate they have to pedal to go to their side while their partner has not. to do so. Physics says that the rate of fall of a body is independent of mass : a lead ball and a plastic ball of the same size fall at the same speed. Therefore, we could assume that, in the case of cyclists, they should arrive at the same time regardless of their mass. However, this is not the case.
When a cyclist descends a slope, there are three forces at play: the parallel-to-ground component of his weight, which pulls him down, and two frictional forces. One is aerodynamics, which depends on the area that the cycling body offers to the air; the other is that of the wheel against the ground. A thick person offers more area, but also his weight is greater, and this one, in the end, wins: the resistance of the air goes with the square of the speed and the mass increases the speed by the cube. Of course, only if the descent is in a straight line. With curves the thing changes due to the centrifugal force, which favors the slim .
Image: US Navy
