Do heavier cyclists experience relatively less wind resistance? I am a cyclist with no physics training (beyond high school). In general, lighter cyclists with high power-to-weight ratios are the fastest, but I am wondering if there is an advantage to being heavier when it comes to wind resistance. My thinking is that, assuming the same body proportions and power-to-weight ratio, the surface area-to-mass ratio decreases as the weight/size of the rider increases, which should be advantageous with regard to wind resistance.
Am I on the right track here or missing something? Obviously the mass of a cyclist influences many other factors beyond wind resistance, but I am curious about wind resistance specifically.
 A: Yes sir, you are on the right track (but we will see that actually, both cyclists will be under de same drag force, in magnitude). We can verify this by using some reasoning and the Drag equation, so lets take a look at it: $$F_D=\frac{1}{2}\rho 
v^2C_DA$$ where $F_D$ is the drag force, $\rho$ is the density of the fluid, $v$ is the speed of the object relative to the fluid, $C_D$ is a dimensioless coefficient (namely, the Drag Coefficient) determined by the object´s properties, and $A$ is the cross sectional area.
Reading this formula, it is evident that - supposing the two objects have the same cross sectional area, same speed and are travelling through the same fluid, but different weights - the drag force will only be different due to $C_D$. But it is known that this term is proportional to the Reynolds number, which is:$$Re=\frac{vD}{\nu}$$ with $D$ being equivalent to the diameter of the object and $\nu$ the kinematic viscosity (which is related to the fluid).
Knowing all of this, we see that for the situation you proposed, the drag force would be the same for both of the riders (drag force is not related to the mass of the object). $\text{But, as the heavier one have more inertia, it will be harder to slow him down}$.
Observation: The Drag equation is used when $Re>1000$, but this case is satisfied for a human riding a bicycle.
