Those reasons make sense, flecc. Let me offer another possibility too:
From one point of view, the present system is just a silly mistake. It governs speed by measuring the rotation of the crank, which is only indirectly related to speed, rather than the rotation of a wheel, which is directly related to speed. If you can do one, you ought to be able to do the other.
But consider that the electrical parts of the bike are made by Panasonic, and the mechanical parts by Kalkhoff, Biketec, or whomever. Perhaps moving the rotation sensor from the crank to the wheel means moving it out of the part of the bike that Panasonic supplies, and on to the part that the bike builder is responsible for. This would complicate matters substantially, and require a closer integration between Panasonic and the bike builder. It's not that it's hard to do--it's just hard for Kalkhoff of Biketec, whose core competence is bicycle mechanics rather than electronics.
When I'm not on my bike, I do product design for a large publishing house. What I do, for the most part, is to mediate between the technology people and the editorial staff. Fortunately, we have lots of expertise in both areas, and so can build products that integrate editorial content with technology in a graceful way. It would be vastly harder to do what needs to be done if I had to source editorial content from one company and technology from another. And so I might find myself doing silly things, like measuring crank rotation rather than wheel rotation.
I still think this is a foolish mistake. If you put flecc, the Panasonic engineers, and the Biketec engineers in the same room, you'd have an elegant solution within an hour or two. The trick, I suppose, is to get them to do it. And to understand why they haven't, you only need to look at flecc's list.
|