I've gotten some new lights for my bicycle this Christmas and just bought a matching dynamo hub wheel for them.

I've removed my old wheel and put the new wheel in the fork and attached the lights just to test if everything is working. When I spin the wheel the lights (both front and back) turn on, but they are flickering. When I spin the wheel fast the flickering subsides, but they seem to be flickering up to quite a high wheel speed.

Video: https://youtube.com/shorts/ZR2HTmoQSsw?feature=share

Lighting system rigged to the dynamoc hub

Now I understand the discrepancy between AC and DC and how the LEDs in the lighting system required DC and the hub provides AC. I also understand that this will lead to flickering if the lighting system is missing the necessary rectifiers and/or capacitors.

Before I continue putting the tube and tire on the wheel and wire everything up permanently I would like to understand if

  1. my lights (or hub) should have the necessary rectifiers/capacitors and should not be blinking like this and I likely have faulty components.
  2. my lights (or hub) may (or may not) have the necessary rectifiers/capacitors but hand-spinning the wheel is very slow and the blinking will not persist at normal riding speeds.
  3. my lights (or hub) do not have the necessary rectifiers/capacitors, but the blinking seems extreme and hand spinning should easily provide enough speed for the blinking to subside and I have likely faulty components.

Now I also found this post, but frankly wasn't sure how my manual wheel spinning compares to bike pushing or if this specific behavior is expected with my specific lighting system.

I am using a Shimano 3D37 Dynamo Hub, FOXEYE StVZO LED Dynamo Headlight and Busch + Mueller Line Brake Plus Rear Rack LED Light.

I would appreciate other peoples thoughts on this. I would like to avoid having to assemble, disassemble and reassemble the entire front wheel and lighting system if it turns out I indeed have a faulty component. I understand that this might not seem a big deal for competent bike mechanics and enthusiasts, but this is the first time I am replacing a front wheel and lighting system like this and I'm sure it will take me hours. Thank you!

  • 3
    Hand-spinning is slower than you think as well
    – Chris H
    Commented Jan 18 at 21:26

1 Answer 1


Shimano hubs and B&M lights should work nicely together. I've used that combination in the past.

You need to ride around for a few minutes to charge up the capacitors that power the stand-lights and steady the front light's beam at lower speeds.

Take a ride around the block. I bet you'll be pleasantly surprised.

  • 1
    Thank you. This is what I was hoping. I'll install everything and will give it a shot. Commented Jan 18 at 20:43
  • 4
    With a lot of decent lights, it takes around 10 seconds for the capacitors in the anti-flicker circuit to charge, but a few minutes for the standlight cap to charge. They are separate (at least in the lights I've stripped down) which makes sense from an electronics point of view
    – Chris H
    Commented Jan 18 at 21:25
  • 6
    I assembled everything and took a spin around the block. Everything worked great, thank you! Commented Jan 19 at 0:42

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