Originally Posted by
robert schlatte
I have two Shimano dynamo hubs. When the hub is charging I can feel a faint buzz when velocity picks up such as when you are going down a hill but it is negligible and quickly forgotten. I have ridden all day with the dynamo charging USB devices and have absolutely forgotten it was charging.
Same thing with my Shimano and Schmidt hubs. The frequency is low enough that I can't hear the vibration (usually between 15-18 mph), even over the road noise from my slick tires.
I've also run lights for hours (in daylight) and never noticed it. After I switched the lights off, I couldn't tell a difference.