Dahon.Steve ... you mentioned dynamo lights in the previous post. This is getting a bit off topic, but the Batavus I just bought (to replace my stolen bike) came with roller brakes and the dynamo is built into that.

I think they use magnets to generate the electricity as there is no change in the drag if the front light is on or not. This was all new to me and came as a pleasant surprise. I'm sure I pay a small penalty in weight, but since I use my bike for pleasure and not for racing, it's not a big deal. This 'dynamo' makes no extra noise and produces no extra (as far as I can tell) drag.

Someone in this thread mentioned the police and how they usually don't enforce the law re lights on a bike. I actually seen the Dutch police control groups of bikers ... if it's dark and your light isn't on or broken, you can get a ticket. You'll read about that the next day in the paper.

... the off topic police will be giving me a warning pretty soon ...