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Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 9:38am
by velo-city
Hi, I've just recently had a wheel made with a new Shimano 3N80 hub, powering B&M Cyo RT light and an E-werk.

All seems fine in technical terms - the lights run and my batteries charge. Brilliant!

Apart from the time taken in getting a wheel built and running wires all over my bike (which took some time to get on even relatively neatly), I couldn't be happier....

...EXCEPT, the hub's quite noisy.

When any power's drawn, it makes a reasonably loud 'buzzing' or 'pulsing' noise, which kind of distracts from the peace of cycling. Much louder for the lights than doing USB charging - I imagine due to the increased load.

Perhaps this is 'normal', but I was under the impression the advantage of hub dynamo's was that they're silent. That's certainly what I was expecting.

Any one else have this same hub with/without noise, or experience noise on any other dynamo hubs?

Just need to know if its something I have to live with, or need to go through the arduous task of getting a new one and a new wheel rebuilt!


Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 9:44am
by The Mechanic
I have had exactly the same hub for about 5 years now. Mine does not make any noise at all either on or off load.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 9:49am
by NUKe
If its new take it back. Mine is silent just liek the mechanics

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 10:14am
Are you sure it's not the light? I have a Cyo that took to intermittently buzzing. It stopped when I grasped the light. I think I've traced it to the loose wires under the body meant for the rear light. I shall glue them with a weak adhesive.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 10:21am
by velo-city
Thanks for the replies, that's just what I needed to know....

Pretty sure its not the light. With light off, and power being drawn from the e-werk to charge something, it makes the same (but slightly quieter) noise.

Apart from the hassle of getting a new one, it looks like I'm going to have to have to pay (and wait) for a new wheel to be built (again), plus all the shipping costs etc. Not happy! Mmmmmm.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 10:37am
by velo-city
Having now put the bike on a stand to test, the noise is also associated by a strong vibration through the wheel. Mmmm.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 10:45am
by PW
With a Schmidt you'd get that vibration at slow speed on a work stand as the poles go past the magnets but it feels smooth as silk on the road.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 1 Mar 2012, 5:56pm
by andrew_s
I'd guess that the noise only happens over a certain speed range.

If so, it's the vibration from the magnet poles resonating with something a little loose that causes the noise. On my bike it comes from the D-ring on my RH bar end shifter. On your bike it could be just about anything that will move - loose bolts, mudguards or mudguard stays, brake levers etc. Once you've found it, a small amount of blu-tack in the right place should stop it.

On a smooth road and with the light on, you may well be able to feel the vibration in the handlebars The more current the hub is giveing, the stronger the vibration will be. A new hub will do the same, unless it's a different model with a different number of poles that vibrates at a different frequency.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 2 Mar 2012, 10:21am
by velo-city
Thanks Guys

No, this vibration and noise was at all speeds, although obviously increased proportionately from zero up to a point.

Even riding at 25 mph, the vibration and noise was loud, and could be felt on the bike. On a stand, spinning the wheel fast, it vibrated the whole bike!

So, I took the plunge and sent it back for a refund. To be frank, if a dyno hub runs anything like the one I had, I'll abandon the plan anyway - there's no way I'm riding with that noise/vibration!

Sadly, that meant dismantling my new (only 1 day old) hand built, wheel, posting hub back to Germany, and waiting for my refund, while I ordered a replacement from another supplier. I then have to send my dismantled wheel parts, and the new hub (when it arrives) back to the wheel builder, and pay to have it done again. Plus all the postage costs and hassle. Urgh.

I saw here and some other forums people saying how cheap al the dynamo stuff is from the German suppliers, and they're right, but when I saw one post about warranty issues, I just shrugged it off and ordered form there anyway. "It's so cheap it's worth the risk - and what are the odds of getting a duff" I thought.

Well, I'm eating those words now! I used Rose the first time - never again. This time I've gone for another German place since I'm already this far down the line.

What are the chances of two being duff!.....

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 2 Mar 2012, 10:55am
by The Mechanic
Don't be put off dynohubs. Despite what some posts have claimed, you should not feel any vibration from the hub. My audax bike runs exactly the same whether I am using the dynohub wheel or an ordinary hub wheel. I cannot tell the difference and there is certainly no noise and no vibration.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 2 Mar 2012, 11:00am
by [XAP]Bob
Slow spinning on a stand, so without any significant mass on the bike, all hub dynamos will cause some vibration as the various poles and coils pass.

On the road the additional mass on the bike, and therefore increased inertia kill this vibration. On my SON I can't feel or see it at all - this is on a trike, so I sometimes watch the outside of the hub from less than 2' away as I go round a corner at speed ;) and it's always in the corner of my eye (where the eye excels at detecting motion).

At very low speeds I can see the lights flicker as the poles spin, but still can't feel the hub.

Obviously there is a :shock: price difference, but the same principle should apply. There may be a resonant frequency of something on the bike which you want to avoid, but that would express itself as specific speed issues (and multiples of that speed)

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 2 Mar 2012, 11:16am
by s1965c
velo-city wrote: I used Rose the first time - never again.

Don't be in too much of a hurry to dump Rose, though. It's hardly their fault that a Shimano dynamo had a problem. I've found them to be very good indeed, far better than Wiggle or CRC to deal with, especially when things go awry.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 3 Mar 2012, 8:56am
by Meshuga
I have four dynohubs all from Rose and no problems, silent and vibration free. The most recent purchase was a 3N80 and it was fine. I think you were very, very unlucky and it could have happened from any supplier. I feel your annoyance as such a problem was unlikely to come to light until the hub was built up ans spinning in a wheel.

The way I see it, a fault in a Shimano part has caused you to incur costs. These costs were unavoidable as the fault could not be detected until the wheel was built. All dynohubs feel horrible and notchy when turned by hand before building because of the magnets. I wonder if you can claim the build cost from Shimano? Agree that's unlikely but maybe worth a try emailing them the wheel builder's receipt and a copy of the returns invoice from Rose. Nothing to lose I suppose...

Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 3 Mar 2012, 9:09am
by Brucey
re the vibration; if any of the parts inside the hub (windings or magnets principally) are very slightly loose the hub will make a noise. It mightn't last either. This isn't the only reason for such a noise but it is high up on the hit list.

Parts could be loose inside due to faulty manufacture or due to handling. Both motors and generators can internally fail spontaneously if (say) they are given a big enough knock.

Although it shouldn't in theory, this could happen if (say) someone simply drops your hub on the floor.

Hopefully the replacement will be a bit better.


Re: Shimano 3N80 Dynamo Hub 'Noise'

Posted: 4 Mar 2012, 12:15am
by velo-city
Thanks guys. All good points. May well drop Mssrs Shimano a line at the end of all this.

Glad to hear spinning the hub alone is hard to check. I did try, and was quite surprised at how hard it was. I was expecting resistance but not so much 'stepping'. I'm guessing its got some serious magnets.

I ended up going for the new black XT branded one rather than another 3n80. Txxx (can't remember model)
I prefer black and since I'm rebuilding the wheel I might as well try another hub.
Fingers crossed.

Got to experience completely dismantling a wheel for the first time. Using nothing but a spoke key.
Amazing that those 36 little spokes turn into a solid wheel really!