Busch & Müller have been manufacturing bicycle lights in Germany since 1925. They offer a wide range of interesting products with most of their lights being targeted for the European market where, unlike here in the U.S., there exists strict standards for bicycle lights.
One of the unique aspects of most “Euro-style” headlights is that they have controlled beams that place the light where it’s needed on the road, similar to well-designed automotive low beams. In contrast, a majority of the lights manufactured for the U.S. market have less-efficient round beams like flashlights. Lights with round beams work reasonably well, but for the same output, a light with a well-controlled beam will provide superior performance on the road.

When a bicycle is used for transportation on a daily basis, the advantages of dynamo-powered lighting become apparent. Eliminating the need to charge batteries as part of a daily routine is reason enough to prefer dynamo systems (there’s nothing worse than getting caught in the dark with fading batteries and a long ride ahead of you). Knowing that reliable lighting is always available with the flip of a switch makes a bicycle more like an automobile and encourages evening and nighttime use. Plus, a dynamo system eliminates the waste associated with charging and disposing of batteries.
Until recently, many dynamo-powered lights were under-powered and only marginally acceptable, but with the advent of ever more efficient LED emitters, the latest crop of dynamo-powered headlights have finally crossed the threshold from “barely enough” to “more than enough”. Among these are the Schmidt Edelux, the Inoled Extreme, and the subject of this review, the Busch & Müller IQ Cyo. These lights aren’t as bright as the brightest battery-powered systems (many of which are inappropriate for use in traffic or on multi-use trails because of their unfocused beams), but they are perfectly suited to on-road use in urban and suburban commuting conditions.

The IQ Cyo is the latest in a long series of dynamo-powered headlights from B&M. It uses their best, rear-facing LED emitter and their most advanced mirror to date. A rear-facing emitter combined with a well-designed mirror make it possible to precisely shape a beam for a specific use. In the case of the IQ Cyo, there are two beam patterns available. The standard IQ Cyo is the brighter of the two with an output of 60 lux. The IQ Cyo “R” has an output of 40 lux. Both use the same emitter, so what’s the difference? The standard beam is shorter vertically; in other words, the beam is is more tightly focused and covers a shorter patch on the road, albeit more brightly. The R’s beam is longer vertically; in other words in covers a longer patch on the road, though because the light is spread out further, it appears less bright on the road surface. [Peter White has some beam patterns here.]

Our test light is the IQ Cyo R N Plus with the taller beam, standard switch, standlight, and integrated reflector. This configuration makes the most sense for urban riding in mixed lighting conditions at relatively low speeds. It puts down a nicely controlled, remarkably bright beam that covers the lane width without spilling too much light off to the sides or into the night sky. If you’re accustomed to halogen dynamo headlights, the Cyo R will be a revelation. On paper, it shouldn’t be able to compete with my twin Fenix L2D’s, but in practice it actually illuminates the road more effectively due to its well controlled beam. For commuters who ride on a mix of urban, suburban, and rural roads at relatively low speeds, the Cyo R is perfect. For those who ride in rural areas at higher speeds, the standard model, with its brighter and more tightly focused beam, might be a better choice.
The build quality of the IQ Cyo is typical B&M ; functional without being unnecessarily extravagant. The case is molded from high quality plastic and the fork crown mount is steel. I particularly like the positive feel of the switch on this light; it’s a step up from the switches on prior B&M lights I’ve used, some of which were a little “soft”. The light comes wired with a long main lead for connecting to a dynamo hub, and a shorter lead for adding a tail light if desired.
Standlights are an important safety feature and I wouldn’t purchase a dynamo light without one. I timed the IQ Cyo standlight’s runtime at over 4 minutes, more than long enough for normal use on the road. I always recommend carrying a second, small backup battery-powered light in the event of a flat tire or other mechanical failure.
The IQ Cyo is available in four configurations as a dynamo light:
- IQ Cyo N Plus (standard on/off switch, standlight)
- IQ Cyo Senso Plus (auto on/off, standlight)
- IQ Cyo R N Plus (tall beam, standard on/off switch, standlight)
- IQ Cyo R Senso Plus (tall beam, auto on/off, standlight)
B&M’s nomenclature can be more than a little confusing. Here’s a glossary to help sort out the cryptic names:
- N = standard on/off switch
- Senso = ambient light sensor automatically turns light on/off as needed
- R = tall beam
- Plus = standlight
Our test light came paired with a Shimano DH-3D71 Ultegra-level dynamo hub mounted on a custom Soma Double Cross commuter. The Shimano hub performed well. I’d offer more input on the hub, but there’s not much to say other than it worked, it produced no noticeable drag, and it provided the correct amount of current to power the light.
Prices have really come down on dynamo systems in the past few years as the technology has improved and the competition has heated up. The IQ Cyo sells for approximately $105—$110 depending upon the particular model. A complete system including a light and a wheel built on a dynamo hub will run approximately $300 (the price will vary depending upon the wheel components chosen). The price may sound a little steep at first glance, but when you consider the fact that the LED emitter will last a lifetime and there are no batteries to charge or replace, you can see it’s a good investment for a full-time commuter.
Dynamo-powered lights have finally come of age and can now provide 100% reliable light at a level that is far past “good enough”. The IQ Cyo is one of the best available, and with a price that’s approximately 50% less than its main competitors, it represents one of the best values in a light for serious bike commuters. Highly recommended.
Many thanks to The Bicycle Business in Sacramento, CA for supplying the test bike and lighting system for this review. —Alan