dynamo light question

Hi everyone,

I am for the first time in my life confronted with the task of buying a
dynamo light system for a bike (I am from Germany, and all bikes just
come with the light system installed).

I'd be grateful for any advice. I have a B+M oval plus and Toplight plus
on my latest bike (in the States). Now I see that B+M sells a 12V range,
and there is a good offer at a German online shop for front and rear
light with standlight. Will this work with a 'cheapo' Axa HR dynamo? Will
I not get any benefit out of its being 12V if I run it with a regular
'cheapo' dynamo? Sorry, am a physics dunce.

In general, does anyone have a recommendation for a LBS in London
(preferrably NE) that does dynamo systems? In general, will LBS's groan
if I ask them to install a dynamo system that I bought somewhere else? Or
maybe I could tackle the project myself...

Any advice greatly appreciated!

m.

Marianne Promberger wrote:

I'd be grateful for any advice. I have a B+M oval plus and Toplight plus
on my latest bike (in the States). Now I see that B+M sells a 12V range,
and there is a good offer at a German online shop for front and rear
light with standlight. Will this work with a 'cheapo' Axa HR dynamo? Will
I not get any benefit out of its being 12V if I run it with a regular
'cheapo' dynamo? Sorry, am a physics dunce.

You'll not get the juice you need without getting a better dynamo (i.e.,
the B&M S12), as that's where the power is coming from.

But, moving off at a tangeant, I'd suggest moving away from bottle
dynamo systems (ones that run off a roller on the tyre) altogether and
get a dynamo hub. The best one is reckoned to be the German Schmidt
SON, but the newer Shimano ones are almost as good for substantially
less money. You'll need a wheel built around the hub as well as the hub
itself, which adds to the cost :-(

Dynohub systems are more reliable (there's never any slippage), silent
in operation, clutter the bike less and are just much nicer in use.
Your existing B&M lights will work fine with them (though you may need
to add a switch in somewhere).

I run a bottle system on my freight bike as it has a one-sided fork and
won't take a dynamo hub. My folder and tourer both have SONs and there
is really no comparison as to which is better in regular use. If you've
got the money then IMHO a dynohub is a much better way to go.

http://www.bikefix.co.uk/ should probably know their dynamos, and sell
SONs, though if you get a suggestion from a local then it will be based
on more first hand experience than I have with London bike shops. And
at least around here, LBS was very happy to build a wheel around a
dynohub I already had and get it all fitted.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On 07/08/2005 14:59:28 (Marianne Promberger) wrote:

Hi everyone,

I am for the first time in my life confronted with the task of buying a
dynamo light system for a bike (I am from Germany, and all bikes just come
with the light system installed).

I'd be grateful for any advice. I have a B+M oval plus and Toplight plus
on my latest bike (in the States). Now I see that B+M sells a 12V range,
and there is a good offer at a German online shop for front and rear light
with standlight. Will this work with a 'cheapo' Axa HR dynamo? Will I
not get any benefit out of its being 12V if I run it with a regular
'cheapo' dynamo? Sorry, am a physics dunce.

In general, does anyone have a recommendation for a LBS in London
(preferrably NE) that does dynamo systems? In general, will LBS's groan
if I ask them to install a dynamo system that I bought somewhere else? Or
maybe I could tackle the project myself...

Any advice greatly appreciated!

m.

The 12v is generated by the dynamo, your cheap dynamo will be 6v at
best, the B&M unit is very low loss and very efficient, well worth
having.
--

Buck

I would rather be out on my Catrike

http://www.catrike.co.uk

Buck wrote:

On 07/08/2005 14:59:28 (Marianne Promberger) wrote:

Hi everyone,

I am for the first time in my life confronted with the task of buying a
dynamo light system for a bike (I am from Germany, and all bikes just come
with the light system installed).

I'd be grateful for any advice. I have a B+M oval plus and Toplight plus
on my latest bike (in the States). Now I see that B+M sells a 12V range,
and there is a good offer at a German online shop for front and rear light
with standlight. Will this work with a 'cheapo' Axa HR dynamo? Will I
not get any benefit out of its being 12V if I run it with a regular
'cheapo' dynamo? Sorry, am a physics dunce.

In general, does anyone have a recommendation for a LBS in London
(preferrably NE) that does dynamo systems? In general, will LBS's groan
if I ask them to install a dynamo system that I bought somewhere else? Or
maybe I could tackle the project myself...

Any advice greatly appreciated!

m.

The 12v is generated by the dynamo, your cheap dynamo will be 6v at
best, the B&M unit is very low loss and very efficient, well worth
having.
--


about the only dynamo which churns out volts is the lightspin. Any other
is a constant current device which will happily fry your rearlight if
the front bulb fails

For about town use I wouldn't recommend a 12v,6W dynamo. If something
fails you'll have a job finding a replacement. And cost is very close to
a decent hubdynamo. Stick with a S6 or an Axa with some decent lights if
a hubdynamo is out of range.
--
--
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

m-gineering ) wrote:
: Buck wrote:
:
: The 12v is generated by the dynamo, your cheap dynamo will be 6v at
: best, the B&M unit is very low loss and very efficient, well worth
: having.


: For about town use I wouldn't recommend a 12v,6W dynamo. If something
: fails you'll have a job finding a replacement. And cost is very close to
: a decent hubdynamo. Stick with a S6 or an Axa with some decent lights if
: a hubdynamo is out of range.

Thanks all. A hub dynamo is certainly coming up for the future, but I am
just outfitting an old bike here where both a hub and a 12 v dynamo are
definitely out of range.

The entire 12 V idea came up like this: London store(s) that I checked
only carry B+M plus standlight range for much more money than I expected
to spend. Tried to find German online store with typical less pricey,
solid but not necessarily standlight (esp front) options. At one, I could
get the 12 V lamps for the same price as the standard B+M over here.

But if they're no added benefit on their own, I'd rather take the benefit
of getting something here with no delay. I really do like to have a bike
to rely on for getting around, no use without lights.

Thanks again,

Cheers
m.