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.

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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
http://www.peterwhitecycles.com/lightingsystems.htm
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