Shimano 3N80 Dynamo Hub 'Noise'

For discussions about bikes and equipment.
velo-city
Posts: 33
Joined: 17 Aug 2010, 11:33pm
Location: London, UK

Shimano 3N80 Dynamo Hub 'Noise'

Post 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!

Thanks
The Mechanic
Posts: 1922
Joined: 23 Jul 2010, 1:38pm
Location: Scotland

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
Cancer changes your outlook on life. Change yours before it changes you.
User avatar
NUKe
Posts: 4161
Joined: 23 Apr 2007, 11:07pm
Location: Suffolk

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post by NUKe »

If its new take it back. Mine is silent just liek the mechanics
NUKe
_____________________________________
User avatar
CREPELLO
Posts: 5559
Joined: 29 Nov 2008, 12:55am

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post by CREPELLO »

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.
velo-city
Posts: 33
Joined: 17 Aug 2010, 11:33pm
Location: London, UK

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
velo-city
Posts: 33
Joined: 17 Aug 2010, 11:33pm
Location: London, UK

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
PW
Posts: 4519
Joined: 23 Jan 2007, 10:50am
Location: N. Derbys.

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
If at first you don't succeed - cheat!!
User avatar
andrew_s
Posts: 5795
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
velo-city
Posts: 33
Joined: 17 Aug 2010, 11:33pm
Location: London, UK

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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!.....
The Mechanic
Posts: 1922
Joined: 23 Jul 2010, 1:38pm
Location: Scotland

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
Cancer changes your outlook on life. Change yours before it changes you.
User avatar
[XAP]Bob
Posts: 19793
Joined: 26 Sep 2008, 4:12pm

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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)
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.
User avatar
s1965c
Posts: 257
Joined: 24 Sep 2009, 3:41pm
Location: Devon

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.
_________
LEJoG slug
Meshuga
Posts: 56
Joined: 5 May 2011, 2:13pm

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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...
Last edited by Meshuga on 3 Mar 2012, 9:12am, edited 1 time in total.
Brucey
Posts: 44513
Joined: 4 Jan 2012, 6:25pm

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
velo-city
Posts: 33
Joined: 17 Aug 2010, 11:33pm
Location: London, UK

Re: Shimano 3N80 Dynamo Hub 'Noise'

Post 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!
Post Reply