Originally Posted by
jim p
When I was a kid, I had a bike with a generator lighting system where the generator rolled on the side of the tire. When I used the generator I felt like I was going nowhere fast and I only used the generator when going down hill and when I had to have a light. I am guessing that the generator was probably about a 3 to 5 watt drag on my engine. So this should compair with the loses in the hub. If you put a generator light system on your bike and ride you should be able to decide if the hub is right for you.
I agree with operator, you are guessing wrong. I have a B&M bottle dynamo on my winter bike, and the losses from that are far worse than any transmission inefficiency I've ever experienced. Well, maybe a broken spoke and resulting brake drag are worse.
Top notch hub dynamos would give a more realistic comparison. The SON dynamo for example operates somewhere around 5 watt loss range when switched on. When switched off, the SON claims a 0,5W loss or so.
--J