Bottom bracket generators

On Sun, 09 May 2004 15:13:22 GMT, "Bruce Lange"

may have said:

What are the currently available choices in bottom-bracket
generators? How much does each cost?

Several exist, most are under $20, but you may be unaware of
the fact that they merely mount in the vicinity of the BB,
they do not engage with the drivetrain. They still rely on
contact with the tire (in this case, of the rear wheel) to
drive the generator.

Quoted message said:

How do they compare to sidewall dynamos and generator hubs
in terms of efficiency?

Similar concept, similar results. Not as efficient in terms
of power produced for drag induced as is obtained by a
dynamo hub, from what I understand. Whether they are more
efficient in terms of cost is, of course, a matter of rider
preference and priorities.

Quoted message said:

Can they be engaged/disengaged while riding?

Yes, for the ones I have seen.

Quoted message said:

Also, can a sidewall dynamo be mounted near the
bottom bracket?

It's been done, but there's little if any advantage.

--
My email address is antispammed; pull WEEDS if replying via
e-mail. Typoes are not a bug, they're a feature. Words
processed in a facility that contains nuts.

Bruce Lange said:

How do they compare to sidewall dynamos and generator hubs
in terms of efficiency?

Night and day...

No to sidewall generators.

Bruce Lange said:

What are the currently available choices in bottom-bracket
generators? How much does each cost?

They are quite rare. Sanyo used to make one, maybe still do.
The main problem is that they run on the middle of the tread
so they get covered in muck and have a terrible tendency to
slip in the wet (there is normally a film of water between
the roller and the tyre).

Quoted message said:

How do they compare to sidewall dynamos and generator hubs
in terms of efficiency?

The design hasn't been refined much as they're not very
popular. I don't know of one that reaches the 60-70% claimed
for the best bottle dynamos and hubs.

Quoted message said:

Can they be engaged/disengaged while riding?

Usually not.

Quoted message said:

Quoted message said:

Can they be engaged/disengaged while riding?

Usually not.

Of course they can. Many French rondoneusse bikes have a
gear lever mounted on the back of the seat tube just for
that. Phil Brown

Zog The Undeniable <[email hidden]> wrote in message news:<409e92ca.0@entanet>...

Quoted message said:

Bruce Lange said:

What are the currently available choices in bottom-
bracket generators? How much does each cost?

They are quite rare. Sanyo used to make one, maybe still
do. The main problem is that they run on the middle of the
tread so they get covered in muck and have a terrible
tendency to slip in the wet (there is normally a film of
water between the roller and the tyre).

This is, in my experience, the biggest problem. I have a
Sanyo unit, purchased NOS, and combined with my BiSy
headlight, it's wonderful to use--except when it's REALLY
wet (under misting conditions, things are fine).

However, a friend of mine indicated that it's possible to
remove the roller and cover it with a section of
innertube, greatly increasing the BB generator's
reliability in the wet.

For me, a big part of the advantage of the BB generator is
that you don't have to worry about wearing through your
comparatively thin sidewalls.

FWIW, while the Sanyo unit does not include a provision for
engaging/disengaging the generator while riding, most of the
BB generators currently in production include a paddle
something like a DT shifter that fits the seat tube and
allows you to toggle the generator in/out of contact with
your tire. One fellow I know recently had a bike custom-made
that included a DT shifter boss on the seat tube, to which
he attached an old Campy lever for just such a purpose!

"Bruce Lange" <[email hidden]> wrote in message news:<mUrnc.12396$536.2328390@attbi_s03>...

Quoted message said:

What are the currently available choices in bottom-bracket
generators? How much does each cost?

Don't know. Haven't bought one in over 10 years.

Quoted message said:

How do they compare to sidewall dynamos and generator hubs
in terms of efficiency?

Probably similar to sidewall gens. Inferior to hub gens.
Just keep in mind these solutions, while perhaps

Quoted message said:

Can they be engaged/disengaged while riding?

The old Soubitez (sp?) I had could be engaged/disengaged
while riding by reaching down and flipping the lever. My
Union unit (the best BB gen I ever owned), has a special
cable plus lever on the seattube that made it really easy.

The Union and Soubitez did not "slip in the rain/wet." I had
a Sanyo BB gen too, and it was by far the worst of any I've
owned. I had to ride up to around 15 mph to get full
brightness. The The Union and Soubitez reached full
brightness at around 7-8 mph.

Quoted message said:

Also, can a sidewall dynamo be mounted near the bottom
bracket?

Probably, but why?

"Bruce Lange" <[email hidden]> wrote in message news:<mUrnc.12396$536.2328390@attbi_s03>...

Quoted message said:

What are the currently available choices in bottom-bracket
generators? How much does each cost?

Don't know. Haven't bought one in over 10 years.

Quoted message said:

How do they compare to sidewall dynamos and generator hubs
in terms of efficiency?

Probably similar to sidewall gens. Inferior to hub gens.
Just keep in mind these solutions, while perhaps these are
electrically inferior to hub gens, they are "cheap and
easy," and do a passable job for commuter type service.

Quoted message said:

Can they be engaged/disengaged while riding?

The old Soubitez (sp?) I had could be engaged/disengaged
while riding by reaching down and flipping the lever. My
Union unit (the best BB gen I ever owned), has a special
cable plus lever on the seattube that made it really easy.

The Union and Soubitez did not "slip in the rain/wet." I had
a Sanyo BB gen too, and it was by far the worst of any I've
owned. I had to ride up to around 15 mph to get full
brightness. The The Union and Soubitez reached full
brightness at around 7-8 mph.

Quoted message said:

Also, can a sidewall dynamo be mounted near the bottom
bracket?

Probably, but why?

Take a look at Peter Whites website. He sells quite a few
different types of generators and more importantly is an
excellent source of info. Look at
peterwhitecycles.comlightingsystems.htmOpen ↗ Len D

"Bruce Lange" <[email hidden]> wrote in message news:<mUrnc.12396$536.2328390@attbi_s03>...

Quoted message said:

What are the currently available choices in bottom-bracket
generators? How much does each cost?

Andy Muzi at www.yellowjersey.org usually stocks the Union
model. Sanyo and Soubitez are (I believe) out-of-
production/NOS and are therefore catch as catch can.

Quoted message said:

How do they compare to sidewall dynamos and generator hubs
in terms of efficiency?

Better than "old" bottles. Probably comparable to the B&M
Dymotec 6. Not as efficient as the B&M S6 or Lightspin, let
alone a Schmidt hub. BB generators are quieter than most
bottles (if only by virtue of being further from the
rider's ears).

Quoted message said:

Can they be engaged/disengaged while riding?

Certainly the Union one can be (can't swear to the others).
But the toggle and enclosed cable supplied with the Union
unit are klutzy looking. Arrangements such as that suggested
by Andy M-S elsewhere in this thread are definitely the way
to go if you can figure something out.

Quoted message said:

Also, can a sidewall dynamo be mounted near the bottom
bracket?

Lower is quieter (see above), but lower also tends to be
dirtier (remember rear brakes mounted on the underside of
chainstays?). Also, engaging/disengaging most bottles
involves touching the unit. You can do that on the fly if
the unit is mounted on a fork blade or seatstay -- but not
if it's down by the BB.

A BB generator also makes an OK parking brake, though not as
good as a rubber band or toestrap around a brake lever.

Peter Storey

[email hidden] (Peter Storey) wrote in message
news:<[email hidden]>... ...

Quoted message said:

Lower is quieter (see above), but lower also tends to be
dirtier (remember rear brakes mounted on the underside of
chainstays?). Also, engaging/disengaging most bottles
involves touching the unit. You can do that on the fly if
the unit is mounted on a fork blade or seatstay -- but not
if it's down by the BB.

...

Quoted message said:

Peter Storey

In my experience with a Sanyo BB generator, it was easy for
me to take my foot and trip the little lever on the
generator to engage it, or push the generator away from the
wheel to disengage, while riding. I was frequently removing
and dissassembling the generator in the winter months due to
sand, dirt, and saltwater rendering it a solid mass. Even
so, getting more than two winters use was uncommon before
the generator wheel drum wore through to the magnet.

Bill Putnam, who considers the Schmidt hub a much better
choice for winter riding