Originally Posted by
storckm
With lights on two of my bicycles (that already had front wheels), both of my wife's, and about five of our children's bicycles, bottle dynamos are a pretty practical option. The B&M dynamos are pretty nice: I really don't notice the drag, although I can hear a whirring sound if there aren't any cars around.
I'm surprised you say that because installing 7 such systems involves a lot of time and expense. I prefer dynamo lighting but I don't put it on all of my bikes. I have movable battery lights for bikes that don't have dynamos.