BUSCH & MULLER CYO R -- the perfect bicycle light? a riding report byAndre Jute

BUSCH & MULLER CYO R
the perfect bicycle light?
a riding report by Andre Jute

There are two Busch & Muller headlights sharing the name Cyo.

One is a longthrow model for macho cyclists who claim they ride so
fast all the time that they have no interest in the road surface
closer to the bike because -- see? -- they ride too fast to take
evasive action -- see? Perhaps on German B-roads this would be a
desirable light, but on my lanes it is perfectly useless as the road
in front of the bike is too dark at any speed to see the pothole. Even
on a favourite fast downhill, with sharpish turns following one
another shortly at around 50kph, I prefer the other Cyo.

The other Cyo is the right light for real-life cyclists, as distinct
from poseurs and cafe-racers. It is known as the Cyo R (for built-in
reflector) or Cyo "Nearfield" (for its light distribution). It is in
fact, in my opinion at least, the better light even for fast cyclists
on real roads.

Each of these two lights has three models, all with standlights by
capacitor; a standlight is a charge which keeps shining the light when
the bikes stops moving. So the naming of each type starts with an
unswitched "Plus" (BUMM terminology for a standlight) model for
sidewall dynamos, followed by a switched model called "N Plus", with
at the top a switched model which adds automatic light-sensitive on-
and off-switching called "Senso Plus". The nearfield model adds an R
to the name.

The particular model I'm reviewing is the 175QRSNDi. It is smart to
order you Cyo by model number to be sure you get all the correct
facilities. Check the table in the catalogue, bottom of this page:
http://bumm.de/docu/175q-e.htm

INSTALLATION
I don't have a bike without factory-installed wiring; in particular,
my Utopia Kranich, to which the Cyo belongs, has through wiring
installed specifically for fitting a BUMM IQ light, with a BUMM rear
light (in my case D'Toplight XS Plus) switched by the front light.
Thus installation for me is a matter of bolting the Cyo in and
plugging in the pre-existing cables. For comparison, fitting a simple
wired bicycle computer took twenty minutes, mostly spent working out
wire routing and finding a standoff for the sensor, so I suppose
fitting a Cyo and a rear light plus wiring the whole bike should take
a mechanic no more than 30 minutes and Joe Blow an hour.

However, the supplied wiring harness that came with a retail Cyo had
bare ends to wire at the dynamo side, and the supplied connectors
didn't fit my SON hub dynamo. I was just lucky that I ordered spare
connectors with the bike when I ordered the SON. (And if you have a
Shimano dynamo, be sure to order the special plastic plug unit the
wires require.) The supplied connectors fit other BUMM lights, and
BUMM lighting harnesses, so eventually they will come in handy.

The instructions seem clear enough: it's a two-wire system so plug the
earth to the earth. Were I to rewrite the instructions, I would add
that it doesn't matter which wire goes on which terminal at the
dynohub.

LIGHT THROW
The monicker Cyo "Nearfield" is a bit misleading, as this light
doesn't throw any less distance than the Speedy Gonzales version, it
merely shapes the beam of light to be wider and to throw a substantial
amount of light close to the bike.

You would expect the far field to be compromised (and BUMM says it is,
presumably by measurement) but for practical purposes the end of the
light beam appears to be at the same distance and to be as bright with
either version. The rest of this review will ignore the "racer"
version and concentrate on the universally useful R or Nearfield
version of the Cyo.

The beam is low and flat, very carefully shaped by the back collector
which is the chief glory of the Cyo. The beam seems to me to be same-
sided both sides, thus useful regardless of whether in your country
you ride on the left or the right. BUMM advises aiming the beam ten
metres in front of the bike: which part of the beam, gentlemen?
Perhaps they mean the hotspot, but it is so small and unobtrusive that
in the short ride from my house to the supermarket parking lot where I
normally set up lights I quite stopped noticing it. In any event, I
set up the lights in my usual manner, with the top line -- very, very
well defined with the Cyo! -- around 1m above ground on a wall at
100m.

The Cyo light has such a sharply defined horizon that no one except an
idiot could set up this light in a manner that will irritate
reasonable motorists.

Useful light starts so close to the front wheel that on my Utopia
Kranich the fat Big Apple "29er" tyres necessitated BUMM designing an
especially tall bracket for the Cyo (standard fitting on Utopia
bikes); this bracket is also sold to the general public as 471LH and
is desirable in itself, apart from its height, because it is made of
nylon rather than metal and thus immune to the vibration that can
sometimes crack metal light brackets.

The verge -- where I ride the ditch! -- is strongly lit close enough
to the bike to use it as a guide should oncoming car lights blind you.
That's a very big plus.

There is enough upward and sideways throw so that you can appreciate
how close the hedge is, but overhead trees are not lit as they are
with circular reflectors. A low-flying branch could jump out of the
darkness above the Cyo's horizon and hit you in the face. The Cyo is
so intent on being legal -- by German standards -- and not irritating
drivers with its substantial amounts of light, it has sacrificed the
overhead view altogether. Whether you consider that a good thing, in
that it concentrates the light on the road, or an acceptable risk, or
an unacceptable risk, depends on where you ride.

Behind the defined light on the ditch and hedge, nearer the bike there
is also sideways overspill that is best described as adequate. In an
emergency -- some boy racer keeping his "rally lights" in your face --
this will allow you to look down beside the front wheel and steer by
the edge of the road.

Because of the Cyo's sharp cutoff on a very low horizon, the pickup of
warning signs is totally inadequate. Even looking for signs on
familiar roads that I can place by memory, I failed to spot several
warning signs, including give-way and stop signs, which a rider less
familar with the road would be keen to see before he shoots across a
blind intersection.

My dynamo lights are under my handlebar bag but peering around the
bag, I don't find the sidespill light from the Cyo irritating; there
is little hood above the top 30 degrees of arc of the lamp to keep it
from shining in the rider's eyes.

The Cyo R has another kind of throw: it has a reflector, which the
other Cyo lack, to throw back the lights of vehicles.

RAMPING HER UP
The ramp to throwing useful light is short and steep: the bike sets
off (on level ground) and almost immediately there is usable light
from the Cyo. Setting off uphill also generates light, but it flickers
unsteadily; I don't mind that as I think it attracts more attention
than an equivalently dim but steady light. I would say that 5 or 6kph
is the changeover point to an acceptable steady light, which is a lot
better than lights, even BUMM lights, of only a couple of years ago.

Humans are pretty bad at judging quite substantial alterations in the
amount of light thrown (or any other geometric or logarithmic change).
Thus a Cyo at half output and one at full output will not look much
different to the subjective human eye. However that may be, it seems
to me that a Cyo requires my bicycle (SON, 60-622 tyres with 745mm
circumference) to travel at only 9 or 10kph to put out more light by
far than a 6V Volkswagen Beetle a friend drove when I was student.
Certainly, 13kph seems to bring up full output or something
indistinguishable from it.

About the Senso light-sensitive switching, there is nothing to say
except that it works. It switches the lights (the Cyo also controls
the rear light) on at dusk and in tunnels and in really dark shadow
under trees, and switches the lights off at dawn or on entering
daylight from darkness. There is a delay so that car lights do not
switch off your bike light. It works. But I keep my front light on
permanently; a LED has an effectively infinite lifespan.

FIRST CONCLUSION
Merely as a light to ride with on empty roads, BUMM's Cyo is the best
bicycle road headlight ever made, including battery lights. The Cyo
certainly allows one to ride without big-battery halogen lights that
need to be recharged every hour or so. To be perfect, the Cyo must
allow the cyclist to ride without any battery lights whatsoever.
Unfortunately, all the rest is not roses. The problem is not the
light, the problem is the cars.

THE CYO STANDLIGHT
The Cyo's standlight at first makes an extremely favourable
impression. Push the bike two metres and the capacitor is charged up
enough to shine for a while. You can read a map by it if your eyes are
sharp and you're quick to identify what you want.

Ride the bike a little way, then slow or stop, and the capacitor is
charged up enough to throw full power light for a few seconds and then
a declining amount of light for several minutes, until at last there
only a glimmer, and then the light dies. But you can switch the
standlight off and preserve the charge in the capacitor until you need
it, even days later, say for pushing your bike through your unlit
garden, or starting out up a slow hill.

Impressive stuff out on a quiet lane where I tested the standlight in
the early hours, reading the brief manual by it.

Impressive stuff, at first, even in traffic on lit streets, which are
more dangerous than totally unlit rarely travelled lanes. The Cyo is a
powerful but well-controlled light. I think drivers will see it as
long as it shines so powerfully. But that also inculcates a false
sense of confidence in cyclists, and that power fades away to a
glimmer.

Now, what with street lights and car lights and advertising lights and
building lights spilling out, I believe that the Cyo's exceptional
light throw is just enough (for the first time in dynamo lights) to
make the cyclist safe when he's rolling, or when he first stops with a
fully charged capacitor. How long after he stops before the light
fades to unacceptable is a matter of judgement. The point is that
security demands that the cyclist carry and use a battery light as
well as the Cyo. (I use the small Polaris torch that doubles as my
daylight flasher. On the rear of the bike I have a Cateye TL-LD1100 on
flash mode day and night.)

That is the downfall of the Cyo. A dynamo light that demands that a
battery light be carried for full security is not the compleat dynamo
light yet.

A CRUEL TEST, BUT NOT UNUSUAL
I live up a very steep hill. Though the racers in their peloton, a man
in a car with a bullhorn harrying them, mostly make it up the hill
under pedal power, I am the only civilian (of any age!) to pedal
rather than push up this hill.

The road up the hill is heavily trafficked by automobiles on their way
into and out of town; just out of the countryside, or knowing they're
almost at the town end, they tend to drive too fast. The road isn't
wide, and it is unmarked, and cars are parked on both sides, so these
fast-rolling automobiles cross over into the other half when they can
see nothing coming from the front.

Because the hill is so steep, I ride very slowly. Because I ride so
slowly for so long, the dynamo light doesn't shine and the boost from
the capacitor wears off to where there is just a glimmer of light. So
I can't ride on the road because I can't be certain the cars coming
from the front can see me. It is a humilation, brought on me by my
expensive light system failing me, that I have to ride on the pavement
like a pre-schooler. It gets worse.

The light reaches its nadir of output just when I want to cross the
stream of traffic to reach my house on the other side of the road.
Clearly, even though I can count on the flashing Cateye to keep the
traffic off me from behind, with the Cyo's fairylight glimmer fast
fading to nothing at the front, I cannot count on the opposing stream
of traffic seeing me and not turning me into a road statistic.

That is a failing that the Cyo shares with all other lamps with
standlights. Oh, the Cyo performs marginally better than the D'Lumotec
Oval, which dies altogether at the bottom of the hill, but the Cyo
still misses assuring my safety by a mile.

I'm sure I'm not the only BUMM customer to live up a steep, slow hill
with dangerous traffic. I shudder when I think fo where I lived in San
Francisco many years ago...

IN THE FINAL ANALYSIS
The Busch & Muller Cyo R Nearfield light is the best dynamo light
available for all the reasons named above -- and it is shocking how
far the Cyo falls short of adequacy in its primary function of
assuring the life of its owner among the chariots of steel that infest
the cyclist's space.

BUMM could easily fix what ails the Cyo but only for export markets,
as the fix would be illegal in Germany and The Netherlands. See the
Appendix.

RECOMMENDATION
If you're buying a dynamo light, don't accept anything less than the
Cyo (street price now under 60 Euro), forget about the show-off's
"racer special", accept only the R nearfield version, do spend the
money for the Senso automatic on-off -- and buy and use a small
longlasting LED battery torch to back up the Cyo's standlight when it
fades.

RELATED RECOMMENDATIONS
BUMM's D'Toplight XS Plus is as ugly as only German modernist design
can be -- and a powerfully bright rear light with decent visibility to
the sides; its standlight is powerful and longlasting, though it
fades, just like that of the Cyo. I back it up with Cateye's TL-
LD1100, the only rear flasher that can be seen in daylight. Cateye's
expensive rear light is, constructionally speaking, a piece of crap,
but after my first one fell apart I couldn't find anything to perform
its service as well, so bought a second one. My front daytime flasher
and nighttime auxiliary light backing up the Cyo standlight is a tiny
Polaris*L120W; unfortunately it is too bright to use as a flasher at
night.

APPENDIX
HOW BUMM COULD FIX THE CYO TO BE SAFE

BUMM could easily fix what ails the Cyo.

A fix has in fact been on the market for years in the upmarket
Solidlights. These have software which flash the lamp until enough
current arrives from the dynamo to light it up solidly, and again when
the bike stops, rather than let the light fade away to nothing but a
useless token, when the charge in the capacitor falls below a certain
high point, the light flashes, so preserving it as a warning for a
very much longer time. Perhaps it is time for BUMM to take another
look at the Solidlights -- I'm sure they have a set somewhere on the
premises.

Of course BUMM would be able to sell the Cyo RF (the "F" for
"Forever") only in certain export markets, as the fix would be illegal
in Germany and The Netherlands where flashing lights are streng
verboten. But I think that the work would be justified because it
would clearly be a better light that would find a market.

I'd buy one in a flash.

Copyright © 2009 Andre Jute. Free to reproduce on not-for-profit
netsites, only in full including this notice.

"Andre Jute" wrote in message
...

There are two Busch & Muller headlights sharing the name Cyo.

One is a longthrow model for macho cyclists who claim they ride so
fast all the time that they have no interest in the road surface
closer to the bike because -- see? -- they ride too fast to take
evasive action -- see? Perhaps on German B-roads this would be a
desirable light, but on my lanes it is perfectly useless as the road
in front of the bike is too dark at any speed to see the pothole. Even
on a favourite fast downhill, with sharpish turns following one
another shortly at around 50kph, I prefer the other Cyo.

You've never tried it. The pothole appears in the light ahead of the bike in
time for you to see it, which is how it's supposed to work. Having it appear
near to you is pointless.

I don't believe you've tried both models. You write as if you have, which is
dishonest of you.

There is enough upward and sideways throw so that you can appreciate
how close the hedge is, but overhead trees are not lit as they are
with circular reflectors. A low-flying branch could jump out of the
darkness above the Cyo's horizon and hit you in the face. The Cyo is
so intent on being legal -- by German standards -- and not irritating
drivers with its substantial amounts of light, it has sacrificed the
overhead view altogether. Whether you consider that a good thing, in
that it concentrates the light on the road, or an acceptable risk, or
an unacceptable risk, depends on where you ride.

Interestingly I found the opposite - my IQ lights will show those branches.

Because of the Cyo's sharp cutoff on a very low horizon, the pickup of
warning signs is totally inadequate. Even looking for signs on
familiar roads that I can place by memory, I failed to spot several
warning signs, including give-way and stop signs, which a rider less
familar with the road would be keen to see before he shoots across a
blind intersection.

I wonder if you've simply got yours aimed too low. For me, the warning signs
are really very obvious. Or maybe the non-compromised version of the lens is
in fact better.

RAMPING HER UP
The ramp to throwing useful light is short and steep: the bike sets
off (on level ground) and almost immediately there is usable light
from the Cyo. Setting off uphill also generates light, but it flickers
unsteadily; I don't mind that as I think it attracts more attention
than an equivalently dim but steady light. I would say that 5 or 6kph
is the changeover point to an acceptable steady light, which is a lot
better than lights, even BUMM lights, of only a couple of years ago.

Glad to see you've noticed this. I did say it would do similar some time
ago, but you pretended to ignore me.

Because the hill is so steep, I ride very slowly. Because I ride so
slowly for so long, the dynamo light doesn't shine and the boost from
the capacitor wears off to where there is just a glimmer of light.

Well, you said 5 or 6 kph was the cutover to an acceptable steady light. It
flickers below that before it dies as you describe - so how fast are you
going? I've just tested my Cyo - at 3kph it's producing a decent flickering
light.

I'm sure I'm not the only BUMM customer to live up a steep, slow hill
with dangerous traffic. I shudder when I think fo where I lived in San
Francisco many years ago...

3 kph really is very slow indeed. Not many people can ride below that
speed.

A fix has in fact been on the market for years in the upmarket
Solidlights. These have software which flash the lamp until enough
current arrives from the dynamo to light it up solidly, and again when
the bike stops, rather than let the light fade away to nothing but a
useless token, when the charge in the capacitor falls below a certain
high point, the light flashes, so preserving it as a warning for a
very much longer time.

The Cyo in conjunction with a SON does a good approximation to that.