Originally Posted by
calyth
Not too sure how much that 60 Lux compares to the max 400 lumens...
I guess it depends on the conditions - I tried biking in the dark recently on the Ottawa river parkway, and it was frigging dark (no street lights). I'd want all the lighting I could get.
I'm kinda interested in the dynamo stuff - any pages that I could read up? right now i'm riding something with disc brakes, 700x32c, so not sure whether I want to sink a lot to go for a hub dyno...
Surprisingly the numbers aren't the most critical issue (60 lux vs. 400 lumens). Dyno lights are designed to meet German government specifications, some of which are concerned with where the light is directed. In short, dyno lights are designed with reflector systems (like cars) that place the light where it is needed. My experience with dyno lights (40-70 lux) indicates to me that they place as much (at least) light where it is needed as the 450 lumen battery light I used to use. Now some of the dyno lights are optimized for fast speeds (more light at a distance) or slow speeds (more light closer to the bike) and a few (Luxos U) are designed to sense the speed and change the lighting pattern as needed. Battery lights are designed like flashlights where most of the light (and battery power) is spent lighting the sky...
Now there are battery tail lights that are MUCH brighter then the dyno tail lights, but whether that is needed is an entirely different question.
Best source for information on lighting (and specifically dyno lighting) is
http://www.peterwhitecycles.com/lightingsystems.htm