Soubitez light generator question

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Vintage Dutch Amsterdam 21" Bike

Hi everyone... I'm new to the group and have a question! I

recently

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bought an old Burco Amsterdam bike for commuting purposes on

E-bay. I

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am trying to get the Soubitez lighting system that is on my

bike to

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work. I lack a basic understanding of the "dynamo" that is

attached to

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my front wheel, in front of the fender.

Does the spikey wheel have to be touching the front tire in

order to

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function?

Yes.

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Is it supposed to touch the rubber of the tire or the metal
of the wheel?

The Soubitez I had goes against the rubber side wall of the
tire (NOT the gum sidewall part -- farther out in the black
rubber). Many road tires have a "generator track" on the
sidewall, but not all. A Continental Top Touring 2000 has a
generator track on it, so if you have/can find one you will be
able to see what I'm talking about. It's likely that the tire
that is on this bike has such a track.

It's important that the generator wheel be positioned so there
is no cross-movement as the wheel moves across the tire. This
will create excessive tire wear. This means the generator
must lie straight on an imaginary radius line drawn from the
hub out to the rim. (In other words, it's not that the wheel
is higher/lower where it first contacts the tire than when it
last contacts the tire. If it is, this means it is moving
across the tire and this will create excessive wear.)

Quoted message said:

Also, where is a good place to get new bulbs for these
things?

It may be hard to find the right bulb locally, but you can buy
bulbs (or at least get some specs) at
http://www.reflectalite.com/ They are in the UK but will ship
to US.

--
Mike Kruger
Bike Chicago e-mail list info:
http://www.geocities.com/bvonmoss/bikechicago.html

Quoted message said:

Vintage Dutch Amsterdam 21" Bike

Hi everyone... I'm new to the group and have a question! I recently
bought an old Burco Amsterdam bike for commuting purposes on E-bay. I
am trying to get the Soubitez lighting system that is on my bike to
work. I lack a basic understanding of the "dynamo" that is attached to
my front wheel, in front of the fender.

Does the spikey wheel have to be touching the front tire in order to
function? Is it supposed to touch the rubber of the tire or the metal
of the wheel? Also, where is a good place to get new bulbs for these
things?

Any help would be greatly appreciated!

Brian

Mike's done a good job with the help. But generators are pretty
simple. The tire causes it to spin, and it puts out electricity. Get
a 6 volt, 2.4 watt or 3 watt halogen bulb from Reflectalite - or a
really well equipped bike shop, preferably a non-trendy one. The
trendy ones won't have generator bulbs, and will try to sell you a new
battery light instead. While you're at it, buy a spare bulb. Some
generators have clips inside the headlamp to hold a spare.

Aligning the generator is important, as Mike said. But it may be a
little difficult to describe without a picture. The best pictures I
know of are in the book _Effective Cycling_ by John Forester, which may
be in your library or bookstore. See page 351 of the 6th edition.

Other things to watch for: Obviously, the spring that holds it against
the tire, the pivots, and the latch that keeps it away from the tire
during daytime need to be working properly. But it's rare for them to
have any serious trouble unless the bike was crashed or left to rust.

Sometimes ancient generators get their bearings worn out or ruined by
rust. AFAIK, there's no cure for that.

Some generators (called "block generators"😉 have the headlight attached
directly to the generator body. This can be less than ideal, because
when you get the generator aligned properly to the wheel, the light may
not align properly to the road. Forester's book shows one way to fix
this, and I've used home made spacers, replacement screws, etc. to fix
it in other ways.

- Frank Krygowski

In article <[email hidden]>,

Quoted message said:

Get
a 6 volt, 2.4 watt or 3 watt halogen bulb from Reflectalite - or a
really well equipped bike shop, preferably a non-trendy one. The
trendy ones won't have generator bulbs, and will try to sell you a new
battery light instead. While you're at it, buy a spare bulb. Some
generators have clips inside the headlamp to hold a spare.

I get my lamps from an electronics supply store:
http://www.mainelectronics.com/index.htm

I include the link just to describe the type of
store to look for. They like it if customers can
bring in a sample, to match base type/size etc.

It's a good source for zip ties, too.

cheers,
Tom
--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca

Considering the wide range of speed over which the generator/lamp must work,
how is it made to provide good light at the lower speeds without burning out
the bulb when you ride really fast?

Wed, 06 Jul 2005 06:03:39 GMT,
<[email hidden]>,

Leo Lichtman said:

Considering the wide range of speed over which the generator/lamp must work,
how is it made to provide good light at the lower speeds without burning out
the bulb when you ride really fast?

Modern halogen lamps have a Zener diode voltage limiter built into
them. If you find yourself blowing bulbs, the simple trick for old
lamps is to increase the pulley size on the generator.
--
zk

If you go to an electrical supply house and get a rubber grommet
for a switchbox, that has an inside diameter that matches the outer
measurement of the generator wheel, this can increase performance and
reduce drag. My generator's wheel is 3/4" in size. The grommet is
installed around the outside of the generator wheel. It grips the tire
better in wet weather, is very silent and causes much less wear on the
tire. It also slows down the generator revolutions, so it will last
longer. I've found that without the rubber grommet, my generator
outputs full power at about 8 mph and with it, at about 13 mph. If I
ride at least 13 mph at night, I get full brightness, but if you go
slower, the grommet wouldn't be for you. When you go faster than the
minimum speed for full power, the generator continues to cause more
drag, but doesn't deliver any more power. Some advanced generators on
cars have a cutout system, that causes them to not turn any faster than
necessary for full power, but this feature won't be found on lowcost
bike systems.

I stretch the grommet over the metal wheel and put some shoe goo
under and around it to hold it firmly in place. It's important to have
it in the exact middle of the metal wheel and aligned straight.

Steve McDonald

Steve McDonald said:

If you go to an electrical supply house and get a rubber grommet
for a switchbox, that has an inside diameter that matches the outer
measurement of the generator wheel, this can increase performance and
reduce drag. My generator's wheel is 3/4" in size. The grommet is
installed around the outside of the generator wheel. It grips the tire
better in wet weather, is very silent and causes much less wear on the
tire. It also slows down the generator revolutions, so it will last
longer.

Bike shops used to sell rubber generator caps made for this purpose.
Outside of America, they may still sell them.

Quoted message said:

When you go faster than the
minimum speed for full power, the generator continues to cause more
drag, but doesn't deliver any more power. Some advanced generators on
cars have a cutout system, that causes them to not turn any faster than
necessary for full power, but this feature won't be found on lowcost
bike systems.

Actually, bike generators are elegantly self-regulating to a large
degree. The first graph in
http://www.myra-simon.com/bike/dynotest.html hints at this. The power
output levels off at about 3 watts because the internal inductive
reactance of the generator coils increases with the generator's output
frequency (i.e. speed). In a well-designed bike generator, this effect
largely balances what would otherwise be an increase in voltage
proportional to speed.

- Frank Krygowski

Tom Keats said:

In article <[email hidden]>,

Quoted message said:

Get
a 6 volt, 2.4 watt or 3 watt halogen bulb from Reflectalite - or a
really well equipped bike shop, preferably a non-trendy one. The
trendy ones won't have generator bulbs, and will try to sell you a new
battery light instead. While you're at it, buy a spare bulb. Some
generators have clips inside the headlamp to hold a spare.

I get my lamps from an electronics supply store:
http://www.mainelectronics.com/index.htm

I include the link just to describe the type of
store to look for. They like it if customers can
bring in a sample, to match base type/size etc.

It's a good source for zip ties, too.

That can be a bit tricky. To work properly, giving good light at low
enough speed, yet not burning out at high speed, a generator bulb needs
to be carefully matched to the generator. Since bike generators are
approximately constant current devices (rather than constant voltage),
if you put in a bult designed for, say, 0.3 amp rather than 0.5 amp,
the generator will put out excessive voltage and quickly blow the bulb.
If you put in a bulb designed for 0.7 amp, the generator won't build
up enough voltage, and the bulb will be dim.

I believe this is why generators are standardized at 3 watts, 6 volts,
0.5 amps - so there's only one spec of bulb needed.

In my experience, it's easiest by far to just buy a bulb from someone
selling it specifically for bike generators. But make sure you use
halogen bulbs. They do give much more light than vacuum bulbs.

- Frank Krygowski

The wheel should be touching the rubber of the tire when the light is
on. There should be a pivot that allows the wheel to be taken out of
contact with the wheel when off. As noted by another poster, a touring
tire with a special dyno track molded in is best. Continental Top
Touring and Schwalbe Marathon Plus have good dyno tracks. With a good
dyno track, this kind of generator can function well in rain, allthough
snow will usually pose problems. Without a dyno track, you will likely
lose all illumination if the road is wet.

Peter White Cycles has replacement 6 volt, 2.4 watt bulbs. You will
also need a 6 volt, .6 watt tail light bulb. Many people replace this
bulb with a red LED. Peter White has those, too.

Paul

Quoted message said:

In my experience, it's easiest by far to just buy a bulb from someone
selling it specifically for bike generators. But make sure you use
halogen bulbs. They do give much more light than vacuum bulbs.

And of these the Philips ones seem to be best, for no readily
discernible reason.

Guy
--
http://www.chapmancentral.co.uk

"Let’s have a moment of silence for all those Americans who are stuck
in traffic on their way to the gym to ride the stationary bicycle."
- Earl Blumenauer

Zoot Katz said:

Wed, 06 Jul 2005 06:03:39 GMT,
<[email hidden]>,

Leo Lichtman said:

Considering the wide range of speed over which the generator/lamp must work,
how is it made to provide good light at the lower speeds without burning out
the bulb when you ride really fast?

Modern halogen lamps have a Zener diode voltage limiter built into
them. If you find yourself blowing bulbs, the simple trick for old
lamps is to increase the pulley size on the generator.

The Zener voltage regulator (just two Zener diodes, back to back) helps
a bit, especially with halogen bulbs, which are more sensitive to
voltage variation. But it's just a fine-tuning scheme. It does rather
little of the voltage regulation.

Here's what goes on: First, you must realize that bike generators are
alternating current devices. Many people don't know that.

Now, a generator _would_ put out voltage proportional to speed
(Farday's law, IIRC) but the coils in the generator have inductance, so
they oppose alternating current to a degree, by their inductive
reactance. This is in addition to their resistance, which opposes any
current, AC or DC.

Inductive reactance is given by XL = 2 * pi * f * L where L=inductance
and, crucially, f = frequency. Since the frequency of the output AC is
proportional to the road speed, the inductive reactance is fighting
against a current buildup just as the higher speed of the coils past
the magnets is trying to increase the current.

Briefly, the effects balance out very well. If the generator's well
designed, current remains quite constant above a minimum speed. (It's
useful to think of a generator as a constant current device.) Output
voltage is really determined by the resistance of the load, but it
remains quite constant as well.

Again, the double-Zener regulator just helps flatten the curve a little
bit. It's not always necessary.

A neat trick to try is to put two generator headlights in series. Once
you're up to about 14 mph or so, your generator will be putting out 12
volts, not six volts, as it keeps pumping out its 0.5 amp constant
current. You'll get two headlights shining at full brightness.

This will cause more drag, of course, and if you have a sidewall
generator, it may well slip. But the trick works well with hub
generators. I do it frequently with my ancient Soubitez bottom bracket
generator. (I have a switch to bypass the second headlight at low
speed.)

If you're geeky enough, it's weirdly fun to have a bike that needs a
wiring diagram. ;-)

- Frank Krygowski

Quoted message said:

A neat trick to try is to put two generator headlights in series. Once
you're up to about 14 mph or so, your generator will be putting out 12
volts, not six volts, as it keeps pumping out its 0.5 amp constant
current. You'll get two headlights shining at full brightness.

This is a standard trick with the SON hub generator, which is
particularly efficient, so the drag even when running two lights is
barely noticeable.

Guy
--
http://www.chapmancentral.co.uk

"Let’s have a moment of silence for all those Americans who are stuck
in traffic on their way to the gym to ride the stationary bicycle."
- Earl Blumenauer

6 Jul 2005 07:52:53 -0700,
<[email hidden]>,

Quoted message said:

Peter White Cycles has replacement 6 volt, 2.4 watt bulbs. You will
also need a 6 volt, .6 watt tail light bulb. Many people replace this
bulb with a red LED. Peter White has those, too.

If you do eliminate the tail light and use a LED instead, then be
certain to use a 3.0 watt bulb in the front.
--
zk

Zoot Katz said:

6 Jul 2005 07:52:53 -0700,
<[email hidden]>,

Quoted message said:

Peter White Cycles has replacement 6 volt, 2.4 watt bulbs. You will
also need a 6 volt, .6 watt tail light bulb. Many people replace this
bulb with a red LED. Peter White has those, too.

If you do eliminate the tail light and use a LED instead, then be
certain to use a 3.0 watt bulb in the front.

Actually, I've put a switch on my generator taillight, and often switch
it off. My 2.4 watt headlight gets noticeably brighter when I do that.

I'm sure I'm overdriving that headlight bulb, but so far I haven't
noticed any decreased life. (My bulbs seem to burn out very rarely.)

I've got a 3 watt bulb in the drawer, but I haven't bothered to try it
out yet. Those of you that have, please tell us what difference you
noted. Is it just longer bulb life?

- Frank Krygowski

At 6 Jul 2005 11:06:13 -0700, message
<[email hidden]> was posted by
[email hidden], including some, all or none of the following:

Quoted message said:

I've got a 3 watt bulb in the drawer, but I haven't bothered to try it
out yet. Those of you that have, please tell us what difference you
noted. Is it just longer bulb life?

No, it's brighter, too.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

85% of helmet statistics are made up, 69% of them at CHS, Puget Sound

6 Jul 2005 11:06:13 -0700,
<[email hidden]>,

Quoted message said:

Quoted message said:

If you do eliminate the tail light and use a LED instead, then be
certain to use a 3.0 watt bulb in the front.

Actually, I've put a switch on my generator taillight, and often switch
it off. My 2.4 watt headlight gets noticeably brighter when I do that.

I'm sure I'm overdriving that headlight bulb, but so far I haven't
noticed any decreased life. (My bulbs seem to burn out very rarely.)

When I noticed my headlamp being brighter it was because the tail lamp
had burnt out. After the second or third descent the front one was out
too. That's happened twice. Once was a worn out bulb and the second
was because I'd cooked the tail lamp while spinning the front wheel
while the bike on the stand without the head lamp connected. I didn't
notice it not working when I went out with the new headlamp bulb. The
new bulb seemed much brighter but only for an hour. Result: three new
bulbs in less than twenty four hours. <grrrr>
--
zk

Perhaps I was too late in posting this. When I bought the used bike,
the tires were shot. I took it to a bike store and had them put on new
tires. It says that they are "Tri Sport" tires by specialized. Is it
possible that these tires are too thin to effectively cause the
generator wheel to turn?

I have tried repositioning the generator higher and lower on the metal
structure that it is designed to be on on the front wheel and it just
doesn't come close to connecting. Will it only work with a fat tire?

Brian said:

Will it only work with a fat tire?

It'll work with any tire, but better if that tire has a track, I use a
danish bottle generator on my city bike's slicks and it grips just fine.
You might have to bend the whole assembly to make it happen, but do be
careful.

😉

Brian said:

Perhaps I was too late in posting this. When I bought the used bike,
the tires were shot. I took it to a bike store and had them put on new
tires. It says that they are "Tri Sport" tires by specialized. Is it
possible that these tires are too thin to effectively cause the
generator wheel to turn?

I have tried repositioning the generator higher and lower on the metal
structure that it is designed to be on on the front wheel and it just
doesn't come close to connecting. Will it only work with a fat tire?

Can you describe how the generator attaches to the front fork?

Here's why I ask: Most generators have a mount made of several pieces
of metal held together with screws. This mount clamps around one fork
leg, and the generator body screws to the front end of the mount. With
this type, if the generator's roller doesn't contact the tire when
engaged, you need to loosen the rear clamp screw, pivot the mount to
move the generator closer to the tire, then re-tighten the clamp. Keep
the generator roller about 1/4" away from the tire when the generator's
clicked off. It should get plenty of traction when it's clicked on.

But there is another, better, but much less common mount. Some utility
bikes have a piece of metal permanently brazed onto the fork leg, with
the generator mounting to that. I've never had a bike with that, but
the advantage would be complete freedom from the clamp slipping. The
disadvantage might be that adjusting the generator position could be
trickier. It might require some use of washers or other spacers to get
things right. It may also require some bending of metal.

This is one of those mechanical things that some people figure out
instinctively - or rather, because of long experience at tinkering.
With the difficulty you're having, you may want to call in
reinforcement troops - say, a mechanically skilled friend, or a bike
mechanic.

One caveat: Anything near your front wheel must be attached rock
solid. You don't want anything to vibrate loose and swing into your
front spokes. That can throw you off the bike. I often use Loctite
(the blue removeable variety) on any mission-critical screws like that.

BTW, if you could post photos of the bike, including a close up of the
generator and its mount, we could be more helpful.

- Frank Krygowski