Quote Originally Posted by 246marathon View Post
I try and keep my cadence at 70-80 rpm for 20-25 miles as an aerobic base building workout, but the mph are only about 14-15. If I increase the cadence, I have to down shift and often feel like my legs are moving too fast for the pedals. I can hit 90-100 for a period, but the speed drops lower 12-14mph.
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Exactly my experience. The higher cadence / lower gear it feels like I'm moving too fast, not efficient. My goal is to get aerobically fit enough to maintain the 85-90rpm range (which feels pretty good) but with the power/strength I was pushing at 65rpm. Suspect that will both give me speed, but optimize my riding, find my zone. We'll see...but that's my plan/theory.

And thanks to all who have joined in and responded in this thread. Fascinating stuff, from the fast/slow twitch to the heart rate stuff.