Bottle dynamo noise

General cycling advice ( NOT technical ! )
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Velorum
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Bottle dynamo noise

Postby Velorum » 14 Mar 2010, 8:55pm

I have little experience of dynamo's........

The bottle dynamo fitted to the Mighty Sparta is awfully noisy - pedestrian's turn round to see what that strange noise is.

Should I be messing about with the mounting bracket on the fork to reduce the pressure or leave well alone?

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Last edited by Velorum on 14 Mar 2010, 8:58pm, edited 3 times in total.

gbnz
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Re: Bottle dynamo noise

Postby gbnz » 14 Mar 2010, 8:57pm

I've a Axa dynamo, twelve months old, makes a racket (Pedestrians 20' turn to look). I'd adjust it to ensure the pressure applied to the tyre is as light as possible and then accept everyone will hear you coming

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Velorum
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Re: Bottle dynamo noise

Postby Velorum » 14 Mar 2010, 9:00pm

When refurb time comes I may well consider a hub dynamo set up.

gbnz
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Re: Bottle dynamo noise

Postby gbnz » 14 Mar 2010, 9:16pm

I'm thinking of heading back to batteries. My dynamo's, taking into account blown bulbs, bent brackets, tarnished wire and connections,snapped spade connectors, vandal damage, is costing more than my removeable Cateye batterry LD600's to run.

And definately a huge maintenance commitment in comparison.

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Velorum
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Re: Bottle dynamo noise

Postby Velorum » 14 Mar 2010, 9:21pm

The Mighty Sparta has a front light only dynamo set up - reat lights are LED - a good arrangement I think.

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Mike Sales
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Re: Bottle dynamo noise

Postby Mike Sales » 14 Mar 2010, 9:44pm

Velorum, it looks to me as if the axis of rotation of your dynamo is not on a radius of your wheel. If this is so then the pulley will be scrubbing sideways as it turns. Aligning it accurately may reduce the noise (and wear). WD 40 and a better bracket and a little care can reduce the other problems, though not the vandalism.

Mike Sales

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Velorum
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Re: Bottle dynamo noise

Postby Velorum » 14 Mar 2010, 9:51pm

Mike Sales wrote:Velorum, it looks to me as if the axis of rotation of your dynamo is not on a radius of your wheel. If this is so then the pulley will be scrubbing sideways as it turns. Aligning it accurately may reduce the noise (and wear). WD 40 and a better bracket and a little care can reduce the other problems, though not the vandalism.

Mike Sales


Hmm.....looks like some cautious bracket bending migh be in order!

Front battery lights are tempting but I dont think that they woulld match my B&M headlight!

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PRL
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Re: Bottle dynamo noise

Postby PRL » 14 Mar 2010, 10:27pm

Velorum wrote:
Mike Sales wrote:Velorum, it looks to me as if the axis of rotation of your dynamo is not on a radius of your wheel. If this is so then the pulley will be scrubbing sideways as it turns. Aligning it accurately may reduce the noise (and wear). WD 40 and a better bracket and a little care can reduce the other problems, though not the vandalism.

Mike Sales


Hmm.....looks like some cautious bracket bending migh be in order!



Tricky - from the photo it looks as if the dynamo should be rotated around its fixing for squareness. The problem is that this would place the pulley above the dynamo track on the tyre. The negative side of having a brazed on fitting - the bodges that most of us have to make are at least adjustable.

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Velorum
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Re: Bottle dynamo noise

Postby Velorum » 14 Mar 2010, 11:37pm

Or on the other hand....

http://www.bobbinbicycles.co.uk/Retro-Front-Light

I am giving this serious consideration

(With emergnecy LED's in the pannier this might be a good option)

if i go for this option then the B&M front lamp and AXA dynamo will be availale.......

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james01
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Re: Bottle dynamo noise

Postby james01 » 15 Mar 2010, 9:19am

Looking at the photo it seems that the moulded "tread" on the tyre and on the pulley wheel are incompatible, and will promote slippage and therefore noise as the pulley struggles to mesh with the sidewall.
My Axa dynamo, mounted on the rear wheel, is almost inaudible. I've had bikes with fork mounted dynamos that certainly sounded a bit frantic, I think the fork has a kind of sounding board effect.

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MLJ
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Re: Bottle dynamo noise

Postby MLJ » 15 Mar 2010, 3:05pm

Just get an insulating grommet - they are about 20mm in size - and put it over the knurled knob of the dynamo. It reduces noise, wear and slippage!

glueman
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Re: Bottle dynamo noise

Postby glueman » 15 Mar 2010, 3:15pm

I'm a fan of bottle dynamos. They have their drawbacks but the advantages are often undersold. For very occasional use clip-on battery lights are great and for continual night use- 400km+ audax, winter commuting - hub generators steal it but for everything in between bottle dynos work well. I use them with small supplementary battery lights and the system works better than it sounds.

They do make a noise however, somewhere between a low hum and a whine, depending on the model.

fatboy
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Re: Bottle dynamo noise

Postby fatboy » 15 Mar 2010, 3:53pm

james01 wrote:My Axa dynamo, mounted on the rear wheel, is almost inaudible. I've had bikes with fork mounted dynamos that certainly sounded a bit frantic, I think the fork has a kind of sounding board effect.


I switched to rear wheel mounting and it's much quieter.
"Marriage is a wonderful invention; but then again so is the bicycle puncture repair kit." - Billy Connolly

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CREPELLO
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Re: Bottle dynamo noise

Postby CREPELLO » 15 Mar 2010, 4:43pm

fatboy wrote:
james01 wrote:My Axa dynamo, mounted on the rear wheel, is almost inaudible. I've had bikes with fork mounted dynamos that certainly sounded a bit frantic, I think the fork has a kind of sounding board effect.


I switched to rear wheel mounting and it's much quieter.

I'd also recommend the dynamo mounted behind the fork, if the attachment is sturdy enough. With the knurled wheel turning in towards the tyre, it looses traction less easily in the wet and is quieter too.

Mike Sales
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Re: Bottle dynamo noise

Postby Mike Sales » 15 Mar 2010, 10:45pm

"Tricky - from the photo it looks as if the dynamo should be rotated around its fixing for squareness. The problem is that this would place the pulley above the dynamo track on the tyre. The negative side of having a brazed on fitting - the bodges that most of us have to make are at least adjustable."

Doesn't the braze on bracket have a slot to allow the pulley to be dropped down a little? They often do.

Mike Sales