Originally Posted by
asgelle
Again hard words. What does dramatically different mean? The y-axis would be shifted to lower values at slower speeds, but other than that, what changes would you expect to see?
From this chart, you could conclude about a 10 watt advantage at 30 mph going from a 20mm rim to a 60mm rim. I would guess that the advantage under 20 mph would be under half of this (or < 5 watts).
The original poster states that he does primarily solo training rides (and frequently gets dropped on group rides). I don't know what his typical riding speed is but I bet it is under 20 mph. In other words, he has to spend megabucks to gain about a 3-5 watt advantage.
He would in all liklihood, benefit far greater from a better training system (maybe a power based system) than from very expensive wheels.