Quality differences in hub dynamos
Generally speaking, there are serious differences in terms of quality and pricing when it comes to hub dynamos. The higher the quality of a dynamo's design and construction, the more fluid and inconspicuous it will operate. That said, it is very possible to find the right dynamo following this basic principle: The higher your mileage, the better the dynamo should be. Models from SON are manufactured in Germany and are here considered to be top of the line. They run smooth, are durable and robust. However it’s also worth mentioning that models from Shutter Precision or Shimano, such as the PD-8 or the XT DH-T8000-3D, also deliver great performance. Shimano offers the widest range of prices and quality levels and offers a hub dynamo to fit every budget. Shutter Precision offers the widest range of colours and, like SON, has some very special designs in its range. While lights can be replaced (and thus upgraded) quite easily, changing the hub dynamo at a later date is rather costly. This is another argument for choosing a higher quality model, especially if you’re in doubt.
Of course the hub dynamo and rim must have the same number of holes, and the spoke length must be calculated precisely to the wheel’s construction. Because hub dynamos have a high hub flange and the spokes are generally less bladed, they give the front wheel a lot of lateral stiffness. The lacing and centring of a hub dynamo wheel does not differ at all from that of a conventional front wheel.