Well, I'd sound ridiculous trying to pretend I'm a weight weenie, but I can't say I ever noticed the weight of the older Shimano dynamo hub on my Trek. I suspect that, sitting at the centre of the wheel there, a weight difference would as a percentage have to be very much larger to be noticed than on far out on the rotating mass at the edge of the rim.
As Il Padrone has already said, the only difference between the cheapest and the most expensive Shimano hub dynamos is the bearings, the "sports" versions getting Ultegra-level bearings. That might have an influence on longevity, but all the Shimano hub dynamos are rebuildable. In theory that is, 'cos the rebuild kit, if you can even get one, probably costs more than a new complete wheel with hub dynamo at the discounters, as we have just seen.
In the days before I grasped that eventually, as long as you avoid becoming a fashion victim, all cycle components cost the same, the expensive ones just lasting longer, I went into the Shimano dynohubs thoroughly. This was back when the top Shimano dynohub was the NX70, still today offered for sale here and there and still pricey compared to what else you can get from Shimano. I discovered then that all Shimano hubs weigh the same, because of the impossibility of actually getting a sport model (Ultegra bearings) delivered without the heavy disc brake plate. Shimano of course weighs them in the lightest model and that's what appears on the spec sheet...
To my mind, for Irish conditions which, even for those of us who live in the countryside, always include traffic and at least a bit of stopping or slowing down and then starting or accelerating again, the Shimano has a significant advantage over the SON, which is that it delivers more current at a lower speed than the SON can. Your lights come up to full brightness faster and stay bright at a lower speed than with a SON. This certainly applies on my lanes, and on the few major roads I still go on. To a commuter, I imagine, it would be a killer argument that the Shimano under the most common conditions gives more light...
Andre Jute
