Originally Posted by
mdarnton
This is worth repeating (a second time), with some data. I've been riding a long time and have a naturally lazy cadence, 60 or 70, and haven't felt that it was a horrible thing because I don't strain and am not trying for speed records. I don't ride single speed and I do have a computer on my bike, so I started playing with gearing to see what changes in cadence would do in real life. What I have generally found is that when I feel like I'm in a good place I intentionally shift down a gear anyway just to see what happens. What happens is that my speed jumps UP a couple of MPH! Which was totally unexpected. This happens very consistently! As a result, I am trying to crank a bit faster, get a bit less less lazy. I can't say that it's more work, but keeping up that cranking speed requires some attention because it's against my natural tendency.
You won't be able to test this on your bike, which is why I'm commenting. Keep the larger gear; you'll be glad you have it when there' a hill.
It’s definitely more work to pedal faster, but it lowers the force and required pedal strength.
The internal power requirement of pedaling is an increasing function of cadence and the published data from Formenti’s group appears to increase as the cube of cadence.
Still, the difference between 70 rpm and 90 rpm is only like 0.3W/kg and in many, but not all, riding situations it makes for faster riding.
Otto