short version: Tom is right.. shouldn't be a difference.

long version (sort of): most dynamos have been designed to work with a standard headlight, which used to be a 12 ohm incandescent bulb. However, since LED lights have been introduced and matured, some dynamos are designed for the somewhat lower power requirements of the LED lights. ...plus... some are intended for use at higher speeds, and don't produce enough power at very low speeds to meet the German standards. The smallest Schmidt dynamo fits this description. Not sure about the SP or Shimano hub dynamos, though.

I've used bottle dynamos (and still have two) and I've used hub dynamos (have two). The hub dynamos are much lower drag, and I don't know if I'll ever use my bottle dynamos again. If you do buy a bottle dynamo, make sure you can return it after the first ride.

Have you priced the Shimano dynamos? I've heard that they are fairly affordable.


Steve in Peoria