Commuting - Cadence question

This is probably one of those "well, DUH" things, but I'm gonna ask anyway. I've been doing some reading about biking, and one thing that grabbed my attention is that we're "supposed" to have a cadence of 85-100 - each foot going through a full 100 revolutions per minute.

Why is this considered an optimal range? The only thing I can think of is torque, where I'm in a high gear and not pedaling as fast but doing a bit harder pedaling causing me extra work, whereas a lower gear and faster revs may not be as much work. Is this the point? Or what am I missing?

Human power output peaks around 70 rpm or so. That's why.

As I once learned from qmsdc15, it's the difference between what your lungs could do in high gear/fast spin and how your legs would fare in low gear/slow spin. You ought to strike your own balance, find sweet spot or whatever on this. Hope this helped.

Human power output peaks around 70 rpm or so. That's why.

Huh. That's interesting... research time. :) Thanks!

As I once learned from qmsdc15, it's the difference between what your lungs could do in high gear/fast spin and how your legs would fare in low gear/slow spin. You ought to strike your own balance, find sweet spot or whatever on this. Hope this helped.

It's given me a starting point, along with the post just before yours. Thanks!

Especially over long distances, it becomes obvious, even though it is immediately counter-intuitive: it feels like stomping a big gear is faster and more efficient, but a spin really is. I've *never* seen an audax rider pushing a big gear.