Chesterton

Hey all, I took the wheels off my bike to change the studded tires back to regular ones and when I put the front wheel back on, the lights no longer come on when I spin the wheel.

I know my first step is to get a multimeter or some kind of current detector on the terminals to see whether the hub itself is still putting out current.

But my question is, is it possible to mess up the internal wiring of this hub without opening it up? I noticed that as I was loosening the left-side axle nut, the axle turned with the nut at first, and the power terminal on the other side rotated a bit with it. But that shouldn't be a problem, should it? Turning the axle with the hub stationary is no different from the usual case of the hub turning while the axle is stationary, right? It is possible for the terminal to get disconnected from the generator in some way?

The other, maybe more likely possibility is a break in the wire that runs from the hub to the headlight, but it was working literally the day I removed the wheel, so I'm reluctant to believe that simply disconnecting the wire and reconnecting it could have caused a problem.

What should I be looking at, and also, are there any cautions I should be aware of? Thanks!

fietsbob

a loose axle lock nut had my Shimano hub lose its Ground to the frame..

the folded over wire type plug , common to SP, Shimano and I assume yours, came un plugged from road vibration..

several times...

the Wire gage could be thicker (than B&M used on my headlight) that would tighten up that connection.




...

Chesterton

You know actually, the tech spec refers to a "toothed axle washer" that needs to make contact with the bare metal of the outside of the fork blade but I don't recall putting that back on when I put the wheel back in. Maybe I should check my parts tray and see if I forgot something!

Moe Zhoost

I have the same hub and can provide some comfort. It is not likely that you can mess up this hub by removing it from the bike. The internal armature is attached to the axle and connecter, but this whole assembly is suspended by the bearings and doe not contact the rotating part of the hub. Seeing a bit of axle rotation while removing the nut is nothing to worry about.

I suspect that you have a problem with the connection. Remove your wires from that small plastic clip to see if they the have any breaks. If ok, re-insert and bend the ends over and try again. Fietsbob is right, vibrations will certainly damage thin gauge wires over time. Make sure your polarity is right because if you have them reversed, LED lights will probably not work.

The toothed washer shouldn't be critical unless your light is grounded to your frame. Most installations run an independent ground wire.

Good luck and let us know what happens

Chesterton

So, my set up has the two wires running from the terminal at the hub to the headlight (a B&M Lumotec Classic) and then a double wire running from the headlight to the taillight, with the return from the taillight coming back to the headlight's mounting bracket.

Maybe there never was a toothed washer?

Do you know the correct polarity of the terminal points offhand? I believe I have the positive (white stripe) wire running to the left hand terminal strip. That looks right to me, looking at the instructions sheet.

dsbrantjr

Get yourself a $6-10 multimeter from Harbor Freight or Fry's (or borrow one) to help buzz out what is going on.


IIRC most hub dynamos put out AC not DC so check both before deciding yours is dead.

Moe Zhoost

I run the white strip wire as the ground. It makes no difference as long as you are consistent. A toothed washer would have come with the hub; actually 2, one for each each side. They are there to ensure that the axle nuts stay tight mostly, but will help the ground for one-wire installations. Anyway, no harm in reversing polarity to experiment.