Bottle dynamo noise

Colin Blackburn said:

I'm relatively new to bottle dynamos---previously I have only had hub dynamos or battery
lights---but I have one on my Brompton. Last night as I picked up speed it suddenly mad a loud
schreeching noise and the light dimmed but didn't go out. As I slowed it eventually stopped. The
noise as pretty loud so I decided to switch just the LED lamp for the short journey I was making.
Also, it did this a bit towards the end of last winter but I forgot about the problem over the
summer. What is likely to be causing this? Is it going to be as simple as replacing that little
rubber ring or is it more serious? It's a Nordlicht 2000.

Has it slipped? If it has changed position so it's rolling at an angle to the tyre, and maybe even
touching the rim, that would screech and lose efficiency.

If the position is still perfect, it could be worn internally (though that takes a lot of miles).

Whatever it is, you're wise not to ride through it -- if it's just positioning you could wear the
ring badly, or if it's actually slipping you could wear a flat on it.

Brendan
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland Tel: w +353-61-213147 f
+353-61-202569 h +353-61-390476; Room F2-025 x 3147 "][email hidden]
ul.iebrendan.halpin.htmlOpen ↗

Colin Blackburn said:

I'm relatively new to bottle dynamos---previously I have only had hub dynamos or battery
lights---but I have one on my Brompton. Last night as I picked up speed it suddenly mad a loud
schreeching noise and the light dimmed but didn't go out. As I slowed it eventually stopped. The
noise as pretty loud so I decided to switch just the LED lamp for the short journey I was making.
Also, it did this a bit towards the end of last winter but I forgot about the problem over the
summer. What is likely to be causing this? Is it going to be as simple as replacing that little
rubber ring or is it more serious? It's a Nordlicht 2000.

I suspect it's just slipping. Try increasing the contact force first, then a new roller.

Colin Blackburn said:

Last night as I picked up speed it suddenly mad a loud schreeching noise and the light dimmed but
didn't go out.

I am pretty sure that the dynamo is slipping.

Quoted message said:

What is likely to be causing this? Is it going to be as simple as replacing that little rubber ring
or is it more serious? It's a Nordlicht 2000.

I have three Nordlicht 2000s all set up the same on three different bikes but one slips
regardless of how careful I set it up. I have swapped the three around the different bikes but
the one bottle continues to slip - I have even swapped the rubber rollers. The only way I have
found to stop it slipping is to use the metal roller rather than the rubber one. Saddly the metal
roller is very noisy.

John T. Remove the singers of Spam before replying

Colin Blackburn said:

I'm relatively new to bottle dynamos---previously I have only had hub dynamos or battery
lights---but I have one on my Brompton. Last night as I picked up speed it suddenly mad a loud
schreeching noise and the light dimmed but didn't go out. As I slowed it eventually stopped. The
noise as pretty loud so I decided to switch just the LED lamp for the short journey I was making.
Also, it did this a bit towards the end of last winter but I forgot about the problem over the
summer. What is likely to be causing this? Is it going to be as simple as replacing that little
rubber ring or is it more serious? It's a Nordlicht 2000.

It'll be slipping. Was it raining at the time or had you been through a puddle?

You get the (warning: ignorance of correct terms approaching) problem that once the (static?)
friction between the tyre and the drive wheel is overcome, the drive wheel will slip like buggery
until you get the speed low enough that the (dynamic?) friction can move the drive wheel again. Like
locking a wheel on wet tarmac.

Do Nordlicht do an all weather roller? Check also that the dynamo is correctly aligned - I use a bit
of string tied to the wheel spindle and pulled tight radially. Align the string over the dynamo and
Sight down it.

Tim
--
In space no one can eat ice cream

Quoted message said:

Do Nordlicht do an all weather roller? Check also that the dynamo is correctly aligned - I use a
bit of string tied to the wheel spindle and pulled tight radially. Align the string over the
dynamo and Sight down it.

Thanks for all the response. I'll check the alignment, check out for rollers from Nordlicht and if
all else fails go and see Ben at Kinetics to get a SON fitted!

Colin