Originally Posted by
terrymorse
I can confirm, as just about everyone I ride with is considerably heavier. In order to keep up with them downhill, I need to be more aero, more skilled, and more on my pedals out of each turn.
Steady state downhill coasting speed is a simple static force balance. On one side is:
weight * grade
On the other side is:
(rolling resistance * speed) + (drag coefficient * frontal area * 1/2 air density * speed^2)
A heavier rider descends faster because body mass scales more quickly than frontal area.
Steady state, I agree this is a good representation of the physics. What I am struggling with a bit is that lighter riders also tend to accelerate more slowly at the start of descents. Perhaps they just don’t put as much power into getting up to speed and if everyone coasted they would be more on a par.