Re: Best hub dynamo and LED headlight

On Mar 11, 8:38 pm, Andreas Oehler <andreas.oeh...@xxxxxx> wrote:
Wed, 11 Mar 2009 11:55:57 -0700 (PDT), Andre Jute:

On Mar 11, 1:04 pm, Andreas Oehler <andreas.oeh...@xxxxxx> wrote:

I would prefer if you either write my full email address or delete it.

Not me, pal. Google's software truncates e-mail addresses as an anti-
spam measure.

I read the rest but I've already made my case and proven it. What
remains is a kindergarten spat. I can't be bothered.

Andre Jute
Nobless oblige -- within the limits of efficiency

Wed, 11 Mar 2009 03:58:01 -0700 (PDT), Andre Jute:
On Mar 10, 9:56 pm, Andreas Oehler <andreas.oeh...@xxxxxx> wrote:
Of which type of LED headlight are you talking here? The light intensity
above horizon for modern bicycle headlamps (speaking of the Cyo Sport and
the Edelux) are in the same league as the low-beam of a motor-bike.

Gee, the very best from BUMM, and the same thing hyper-developed by
SON (where you still work, don't you, Andreas?),

Lets discuss the technical facts. Or are you out of arguments?

It is always relevant to notice when one is discussing a contentious
matter that one party has a commercial interest and brings with him
the baggage of his employer's commercial, profit-oriented policies.
Honest people declare such interests before they enter arguments.

Differnt to a lot of people here I don't hyde behind a pseudonym. Would my
arguments be more valid if I call myself "absolut vodka" and use a more
agressive tone?

Perhaps it has escaped you, but
motor-vehicles when approaching a hazard or an indicator of a hazard
switch on their high-beams.

Motor-vehicles should first reduce speed in unclear situations. Only if
there is no one (and this means also cyclistes and pedestrians) around to
be blinded and there is time enough to fumble with the light switch should
someone think about switching on the high-beam.

I'd hate to be killed by the normative case conjured up in fantasy-
land by a prissy-mouthed German engineer who thinks he has the right
to tell the world how they "should" behave. Get real, Oehler, the
world isn't an ideal place.

I just don't want to get blinded. And I don't want to blind others -
independent form the vehicle I use.

What did cyclist say, if you blind them whith your MR11's?

That's an offensive assumption you're making, Andreas, that just
because I have a good light, I use it to blind someone. Shame on your
lack of faith, sonny.

To make his following argument, Oehler cut without notice from my text
a section in which I already answered his next two dumb arguments:

Trimming quotes to the relevant part is good standard in Usenet.

Also most of those roataional symmetric lights cause very high brightness
right in front of your bike, which renders the light in 20m distance
useless. Result: Very good iluminated near field but not possible to look
far ahead, because the eyes get adapted to the brightness level in the
near field.

Crap. I answered the silliness above already, but you snipped my
answer without notice. Here it is, reinstated:

*****
A little light lateral thinking will soon convince you that if one
light throws a particular pattern, two overlapping lights will have a
smoother gradient.

This is not the solution but the problem. If the gradient is not high
enough with the tightest beam available, additional lights of similar or
even broader beam will make the light distribution even worse.

What is needed is a relative even level of illumination on the road and
additional some light above to see signs, branches etc.

Precisely. I'm glad you agree at last that the low, flat, narrow
BUMMSON light isn't ideal for cyclists.

Nice joke ;-)

To reach this you need a light with a relative hard cut-off above the
brightest spot and than a continuous decrease in brightness vertially
down. To have the road in 20m as bright as in 2m you need 100 times as
much candela. Even MR11 lights with the tightest beam don't have such a
high gradient in intensity, which causes a too bright near field and a
comparable dark far field.

They make up for it by being so cheap that you can buy two and arrange
them to give you the light gradient you desire, and in addition they
meet all the other requirements, including the German legal ones,
since your only remaining argument is that the BUMMSON lights are
legal in Germany.

You are really joking - aren't you?

I've just explained to you about twenty times that in my opinion
cyclists do have that need. Cyclists, for a start, are on two wheels
and do not have the stability of four wheels,

What does this mean for the light distribution? In both cases you want to
see the same part of the road.

they sit higher,

The level of the eyes are not so much different. Compare sport cars with
recumbents and upright cyclists with SUVs.

they
travel slower,

This usually means, the stopping distance is shorter - so no 100% need to
look as far as a car driving with low beam.

they're more vulnerable to other vehicles.

Car owners also don't like accidents.

You forgot the lack of a windscreen, which offen causes much reduced view
of car drivers compared to a cyclist.

You're just
not listening, Andreas.

No - I'm only reading :-)

I'm sure that if you weren't an employee of
Schmidt Mashinenbau, with the baggage that implies, this conversation
would flow differently.

I don't think so.

You
won't have such an efficient shaped beam - but for short tours with a
heavy bike it might work for you.

Knock-knock. What has the fact that in those particular photographs I
show a bike weighing 18kg have to do with anything?

Inefficient lights consume more power. This makes a heavy or short-lasting
battery neccessary.

That single sneer tells us why what I say is wrong with the SON hub
dynamo is in fact wrong with it, that it was designed with a road bike
mentality.

If "road bike" stands for "light and efficient" - than I can agree.

And the sneer that I take only "short tours" comes from the same
source.

Let me say it again: Cyclists have different needs from motorists.

In what regard? Both want to illuminate the stretch of road ahead which
would be their stopping distance. Additionally they want to know whats on
the road signs.

And the road verge and the ditch and the branches overhead (and some
roadsigns above pedestrian height but placed just nicely to slice the
top off a cyclist's head) and the signs at blind junctions and the
sign that say tractors crossing at night in harvestime, and so on.

Signs should be visible. I'm not so mutch interested in the ditch ;-) With
a dynamo light or a light battery light you have to decide where to have
the light. Even a high efficient 4W-LED won't put out as much light as two
55 Watt halogen bulbs of a car. It seems wise to leave out the
illumination of the ditch and tree tops - or you would end with an overall
too dim light.

Neither BUMM nor SON will build a satisfactory light for cycling until
they recognize this and act on it.

They do. But you haven't tried their recent products.

Yeah, yeah, yeah. The latest model is always the second coming. And
suddenly the IQ Fly Isn't "recent".

The Fly varies in light distribution, because different types of LEDs are
used and LED can move out of position. So a Fly might be comparable (but
dimmer) than a Cyo - but it is not sure.

You seem to have money to spend and time enough: Get a B&M BigBang.
Brighter than most car low-beams and with the option to modify the beam to
rotational symmetric.

Excuse me? What makes you think I would take an offroad light onto the
pubic roads? Or do you think I'm as irresponsible as you are?

The BigBang is designed and legal for a road bike. Why should its use on
the road be irresponsible?

Only with the additional diffusor you get the rotational symmetric beam
you demand.

But for a start. Find someone with a Cyo and ride some hours in the dark
together. Then report back.

Oh, I'll probably get around to buying a Cyo too. Giving BUMMSON my
money for their latest and greatest, which soon turns out to be not as
good a decorator's lamps, must be habitforming even if it is a stupid
as marrying the woman you just divorced, over and over again. Hope
burns eternal in the bosom of the cyclist.

Would it be better to stop the progress in LEDs, electronics and reflector
design?

The last time you reported to use an old-fashioned DLumotec Oval - about
20% as bright as a Cyo Sport...

So what? That is the light that a few years ago you were touting as
the end-all and be-all of bike lights,

I definitely did not! The DLumotec reused the reflector of the Lumotec12V
halogen bulb. It was not even as bright as a halogen headlight. Heavy, bad
cooling, inefficient electronics and the old-fashioned Luxeon side-emitter
LED. I always prefered the E6 (brighter, more eficient beam). The Cyo is
something developed from scratch with maximum efficiency in mind for
optics and electronics together with the best LED available.

Amazing you didn't comment on this...

So far your strategy to throw lots of text and personal offenses around
didn't seem to convince much people... I publish my measured data and
document the background.

Of course you. That is what you're paid by one of the manufacturers of
hub dynamos and dynamo lights to do.

No. My journalist activity is done in my off time. The magazines pay me.

What would be surprising, though
it will never happen, would be for your opinion to differ from that of
the accountant for Schmidt Maschinenbau.

My opinion differs in lot of aspects from my (part-time) employer. But
this doesn't matter here.

Arrange better measurement setups and publish the data.

I don't have to. I'm a paying customer. The products you're touting do
not satisfy my specific, enumerated needs.

Maybe.

If you were smart, you'd
listen to me and promise to do better.

This would be a more "professional" way nowadays: Tell the customer what
he wants to hear... But I'm too much of an engineer to look for the facts
and not to hear to ...

read more »

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