Originally Posted by
Robert C
I had a Shimano hub on one of my bikes (which disappeared on a flight from Asia. . . long story). The hub had very noticeable drag; so, I just unpluged the wire coming out of the hub when I didn't want the light on.
Yes, this was a problem with older Shimano dyno hubs. The new ones have far less drag (nearly a match for the Son hubs in this regard), particularly if the light is off (or using low power in daylight running mode).