Per Tºm Shermªn °_° ":
That is one of the two points of this particular version of the Schlumpf
2-speed bottom bracket (the other is a wider gear range than is possible
with stock chainrings and front derailers - or to wider the gearing
range where a front derailer is not practical to use).

Ok... it's starting to soak in now: This thing actually delivers
chain movement per pedal stroke that corresponds to
conventional-sized front rings on conventional setups.
--
PeteCresswell