Hmmm, looks like I missed the original post. Apologies in advance for being too lazy to edit my rambling thoughts into a couple of punchy paragraphs. I am the customer JB referred to. Apparently I was also Schmidt's first customer in Africa for the SON (Schmidts Originale Nabendynamo). The details aren't to hand, but it could have cost about R2 500 for the hub and the Schmidt E6 light, plus another king's ransom minor charge from Yellow Saddle for building the wheel. I will have a look for the invoices this evening and confirm. I use it permanently on my audax bike, which is also my commuter. My SON is, I think, the 28. This reaches full output about 15 km/h. Lower-drag models are now available; their advantage is that they impose less drag in normal unlit riding, but reach maximum output at a higher speed. This is fine if you're a fast rider anyway. Plus, these days there's a big selection of suitable LED headlights that shine brighter at lower r/min anyway, so the low-drag units make even more sense. I bought the dynamo setup because of Paris-Brest-Paris. In 2006 I was using two Cateye Super Spot 1W (supposedly) lights that I considered OK until I came screaming down Du Toits Kloof at 1 a.m. in pitch darkness and a howling south-easter - skidmark time. A couple of my fellow riders were using units with big batteries (Sigma and Nightlightning) but I was worried that I wouldn't be able to recharge them on PBP, hence my decision to go with the dynohub. I also liked the idea of generating the light through my own efforts. How does it go? If I'm riding home, like today, and it's getting dark, I never have to wonder if I recharged the battery or brought fresh ones. I simply click the switch and there's light. (OK, you have to be moving, though lights are available with a standlight function that keeps them going for stop streets, etc.) So it's no big deal to use the light as a daytime running light. Yes, there's a weight penalty, but I'm guessing that the better class of battery will weigh much the same. And yes, with the dynohub you can't quickly swap your lights from bike to bike. You also have to be careful that you don't rip out the wires when removing the wheel - just the sort of thing that will happen in the dark on a lonely country road. For such occasions, and for reading my audax cue sheet, I use a tiny light that clips to my helmet and runs off a CR302 cell. Oh, and there's always the faint possibility of pretzelling the wheel... but that's why I keep a small battery backup. Drag is something that's not an issue in normal running. With the light on, initially there's a kind of buzz or tingle in the handlebars. According to the manufacturer, with light on, the drag is equivalent to about half a km/h in 10. Even in my worst moments on PBP I didn't feel the need to switch it off and use my battery backup instead, and at times I was barely clocking 10 km/h. The SON hub is said to be good for 50 000 km between rebuilds. By the way, it can't be user-serviced. Some may see this as a challenge, but I'd rather not. It's on about 6 000 now. As for the light itself, until recently the E6 was Schmidt's top-of-the-range light. Its 6V/3W halogen bulb is run over-volted and is rated for 100 hours; I always carry a spare. The current one is on about 90 hours and still does the job for me. The optics throw a trapezoidal beam - vaguely V-shaped - that looks odd at first. The good thing about it is that the beam puts the light in this tightly focused area, with sharp cutoffs at the side and top (oncoming traffic can see you without being blinded). On the negative side, this might lead to a kind of tunnel vision. People using some of the more recent lights may consider the output of my setup laughably low. Fine; I can't argue with the numbers. But subjectively, I feel comfortable descending at speed even in absolute darkness. I will say that, on PBP when the descents got twisty I also switched on my backup Super Spot because it gave me a wider beam. Basically, nobody could keep up with me on downhills because they simply couldn't see as well. On the flats, I usually had people queuing up behind me for the same reason. Trust me, it wasn't because of my pacemaking abilities. A question has been asked about the use of this kind of hub offroad. If offroad means jeep track or similar, I don't see a problem. My SON is built like a tank. However, using this setup on singletrack would be a waste of time, even with the currently available super-LED head units. You'd just be going too slowly or your speed would be fluctuating too much. These things are designed mainly with road use in mind. That also means the light spread should be concentrated on the road surface; off-road, you'll probably want to see a much wider area around you and above you. For short rides and randonnees up to 300 km a good battery light should be sufficient. However, the dynamo setup comes into its own when you have to start riding through the night and you're unsure of your backup.