Originally Posted by
Road Fan
I'm going to open myself up to flaming again, but in half-step systems, a specific set of chainwheels dictates a specific set of cogs. You can't change the cogset tooth numbers and still have a half-step (assuming what you have is a good half-step).
Generally correct. You can change the range, but not the incremental spacing. This assumes the derailluer has the capacity.
You could replace a 5 speed 14-16-18-20-22 with a six speed 13-15-17-19-21-24 and still maintain half-step progression using the same chainrings.
Michael