Over the last winter I really worked on increasing cadence. I went from spinning around 90 to working on spinning at the 100-105 mark.
Here's what happened today: I do a 120km rest ride. Nothing crazy. I worked the first 95km on keeping my HR down (low zone 3, upper zone 2 (friel's)), and as a result I was only spinning low 90's, and sometimes upper 80's. I tended to stay in a bigger gear and finished the ride with a moving average of 31.5 kph.
Lo and behold, I think I made a mistake this season working so hard to get my cadence so much higher on longer distance solo rides. When I "turned it up" for the last 25km, I had so much left. I hammered the last 25km into a reasonable headwind at 37-40kph, occasional jumps to 45 - and a few up into the low 50's doing the "catch the truck that passed me" routine. I rounded out the day with one of the best times I've ever done on this particular route.
I'm gonna keep playing with it, and not necessarily looking for responses. Just thought I'd post my own findings.
On another note - man, I hope everyone else had the same quality ride I did today. Awesome temperatures, awesome route and zen like mind clearing. Just down right awesome.