Shimano DH-3N80 dynamo hub

Experiences

Tested: From late 2008 to August 2010. About 15,000 km (at least 5,000 km with light on) in all weather conditions, used in a bike that I mostly keep outside, so it has experienced plenty of rain, and I've ridden a lot when it snowed. The bearings are still fine (as far as I can judge without taking the hub apart), I don't feel play in the bearings.

With lamp off: Can't feel the hub (i.e. no noticeable vibrations).

With lamp on: Slight vibration in the handlebar at 22 km/h just as with the SON28 (but much less strong than with the SON28), below that speed there's almost no vibration, and above that speed it gets less until it's almost gone at about 27-28 km/h. For me the vibration is acceptable although less would be desirable. The hub looks nice and although I would have preferred 2.8 or 4.8 mm flat connectors, the wire wrapping method is ok.

Positive points: Works under all conditions, doesn't need maintenance, hub dynamo with approximately the same efficiency as the SON28. Looks nice.

Negative points: Slight vibrations in the handlebar, somewhat flickering light at low speeds (say 5 km/h, this is something almost all hub dynamos have in common), but the vibrations are quite a lot less than with the SON28, and the flickering seems a bit less than with the SON28 too. Strange, 26 to 28 poles is not enough to explain that (perhaps it's the construction, magnet strength and effective induction distance, i.e. how sharp the peak in power production is; I will have to check into this). With light off I don't think I can feel any vibrations, in contrast with the SON28 where even with lights off I could still feel a faint vibration. Note that the vibrations may be less of a problem on your bicycle; it depends on resonating frequencies of your front fork with wheel (including tyre), and wheel + tyre mass. I tested with an old, fairly heavy steel fork. I would not be surprised if with carbon fiber or titanium forks the vibration issue is less (I will test this later).

Note: From about 45 km/h with lights on, the front wheel has a stronger vibration than a SON28. I noticed this on several rides, but as these speeds are not common the lower speed vibrations are generally more important to choose between them. See the description of the Edelux headlamp for more about this.

Conclusion

Excellent hub generator, cheaper and at speeds below 45 km/h less strong vibrations in the handlebat than with the SON28.

Last modified: Mon Dec 3 01:09:01 CET 2012