Dynamo experts plea...
 

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[Closed] Dynamo experts please

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I've built a wheel with a SP hub. Works fine, light comes on, etc but when it's powering the light it's noisy at higher speeds. Is this normal? When I built the wheel it seemed quite stiff and clicky turning it the normal way but this eased with a few spins round. I felt that was the same riding today. I've got it running through a Kemo charger thing too so I can switch the light on and off and there's a definite noise. My only other experience with a hub Dynamo is with the Alpkit one which was smooth from the off. Is it something that needs adjusting or will it just bed in?

Thanks,


 
Posted : 25/03/2017 6:08 pm
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The SP certainly feels notchy when turning it by hand. This is normal as you're effectively moving magnets past each other so there's a repulsion/attraction thing going on. Mine is otherwise completely silent though (and also runs through a Kemo).


 
Posted : 25/03/2017 6:10 pm
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both my SP also silent - as are both my shimanos.


 
Posted : 25/03/2017 6:13 pm
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I've a feeling I read somewhere about adjusting the bearings on them and that's what it feels like I need to do. Strange.


 
Posted : 25/03/2017 6:29 pm
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AFAIK the bearings are not adjustable in any way.


 
Posted : 25/03/2017 6:29 pm
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That's what it looks like.


 
Posted : 25/03/2017 6:33 pm
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As above, I think the bearings can only be replaced at the factory? Mine is also silent when running, but feels notchy to turn by hand.


 
Posted : 25/03/2017 6:38 pm
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I had a faulty one out of the box (well didn't realise until I'd built it into a wheel). Was noisy and had a bit of play in it. Sent it back to Ison.


 
Posted : 25/03/2017 6:41 pm
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I don't think there's any play but I'll check. That'd be a pain to have to send it back!


 
Posted : 25/03/2017 6:45 pm
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MIne was very notchy when turned by hand but was silent - but when you spin the build up wheel in the frame it spins smoothly one you get above a certain speed. From a decent shove with the hand it should spin around 20 turns with the light off and less with it on but should be silent

When the bearings went on mine it was squealing when I rode it but had no play and was still working - the bearings had seized and were turning on the axle

No user servicable parts in the hub


 
Posted : 26/03/2017 10:54 am
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I've built several of these hubs and have 2 of my own. All dynamos are notchy when turned by hand, that's the power being generated! In use they should be utterly silent though.
You have built the wheel so the hub is turning the right way haven't you? There should be an arrow that points in the direction of travel and the terminals should be on the right hand side. Just a thought....


 
Posted : 26/03/2017 11:13 am
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Have read elsewhere that it's due to the design and placement of the magnets.

As above, feels very notchy when turned by hand but totally smooth in use.

IIRC, When the bearings do eventually go, the cost of a replacement from ISON is pretty reasonable.

The CTC did various tests on a handful a few years ago - seem to remember the SP and Son being ever so slightly more efficient than the then current Shimano, but nothing you'd notice in the real world.
The notchy feel of the SP had no measurable effect on resistance or output as far as I can remember.

Link seems to be down at the mo unfortunately, but a more thorough search might find the pdf.

Like mine, but might try a Shimano on the next build just as a comparison.


 
Posted : 26/03/2017 11:29 am
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Yes I'm aware of the notchiness but it was more than that initially. It seemed to be speed and possibly pressure related, ie if I leaned the bike over when riding it was quieter. Having said that I popped out last night and got some speed up down the hill and it was quiet, almost like it needed running in a bit.

It's a disc hub so can't build it the wrong way thankfully!


 
Posted : 26/03/2017 1:29 pm
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Intermittent whirring which coincides with a reduction in brightness of the light. It's going back unfortunately. Just when I'd got the tubeless sorted!


 
Posted : 03/04/2017 12:53 pm

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