Thanks for the review. I think the adage applies "no free lunch." No discernible drag implies that you can't get much light out of it. If the drag were heavy, people would not enjoy using it. I do have a couple of large-wheel bikes equipped with dynamo hubs, and I love those setups, but the headlights are just OK. The light is enough for some situations, but I would not feel comfortable riding on a totally dark road at 15 mph. Most of my riding is in a well lit city, so my headlight is mostly a be-seen light, and it is excellent for that with its German law compliant shaped beam. Taillights for dynamos are also weaker than battery powered lights, and they don't blink. The jury is out as to whether blinking is helpful for harmful.