Busch & Muller dynamo bicycle lights

Busch & Müller
(aka Busch & Mueller, B&M and BUMM)

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Busch & Müller dynamo headlights are made to be powered by a 6 volt, 3 watt hub or sidewall dynamo. The use of Busch & Müller dynamo headlights powered by Velogical brand dynamos or other experimental generators risks damage to the headlight's electronics. Damage caused by overload through such generators is not covered by the one year warrantee!

New for 2018, IQ-XS

The new IQ-XS has similar styling to the IQ-X with a machined and anodized aluminum housing. Unlike the IQ-X the IQ-XS cannot be mounted upside-down.

Available in either black or silver anodized finishes. It has daytime running light, and automatically switches between daytime and nighttime modes. 70 lux.

Busch & Müller IQ-XS Silver, Part # B&M167RTSNDi, Price: $ 96.00

Busch & Müller IQ-XS Black, Part # B&M167RTSNDi-01, Price: $ 96.00

New for 2016, IQ-X

IQ-X headlight

This is the brightest dynamo powered bicycle headlight at 100 lux. The new optical system produces a smoother distribution of light on the road than any other headlight. The housing is anodized aluminum and acts as the heat sink for the LED.

IQ-X headlight

Available in either silver anodized or black anodized finish. The IQ-X has a standlight, as well as daytime running lights. Automatic switching between daytime and nighttime modes. The Senso/Off pushbutton switch is at the back of the IQ-X, surrounded by a glowing blue ring. The IQ-X always provides the ideal headlight beam; straight ahead in daylight so that oncoming car drivers are alerted to your presence, changing over at dusk to a beam optimized for illuminating the road surface ahead, but still providing high visibility to oncoming drivers.

The IQ-X ships with its own highly adjustable mount, and is compatible with other Busch & Müller headlight mounts. For most applications the included mount will work. See the exception below.


Front/Side view of the IQ-X in silver housing.

Note that the back or bottom section of the IQ-X mount, the part that presses against the fork crown, is about 32mm tall. By comparison, the "Cyo" mount, which ships with the Cyo and Luxos headlights, is about 20mm tall, as is the HD Caliper mount, pictured below.


This is the HD Caliper mount on my Rivendell Rambouillet. The spacer between the mount and the crown is 3mm thick. I'd need 6mm or 7mm of spacers to use the IQ-X mount on my frame. Some headsets are thicker than the Shimano Ultegra on my bike, requiring even more spacing.

The taller IQ-X mount will work on most modern forks. But older steel forks with cast crowns, in other words forks that have separate steel blades brazed into a cast crown, typically have the hole through the crown closer to the lower headset bearing than modern forks, and the IQ-X mount will require several mm of spacers behind it to clear the headset. So if you have an older style fork, like I do on my Rivendell bike, you probably want to use a different mount for the IQ-X.

If you have cantilever brakes, you can generally use the Cyo cantilever mount.

The IQ-X is the first dynamo headlight from Busch & Müller that is designed to be used upside-down if you like. The headlight itself still needs to be right-side-up, but the mounting band around the aluminum body itself can rotate around the headlight housing. This mounting band is available as a replacement part. See below.

upside down

Here I have loosened the torx bolts at the top of the mounting band, allowing the entire headlight housing to pivot around so that the mounting point is now at the top. Note that the wiring still comes out the bottom of the housing. The two short wires are for the taillight, and the 70cm long dual strand wire goes to the hub dynamo.

If you are a very silly person who won't be using a wired taillight, you must tape over or shrink wrap the connectors so as to prevent a short circuit. Nothing would be damaged, but the headlight won't work if there's a short. The headlight ships to you with all three wires routed through the body of the mount, and you can't actually see the taillight wires easily. Loosen up the bolts and then slide out the wires. The little section of heat shrink tubing (which hasn't been shrunk) will fall out. It's there to prevent a short if you never loosen that top torx bolt.


The IQ-X mount won't work with older cantilever brakes, so on my old bike I use a different mount that allows the cable to pass right through. This mount is rather long and tall, which puts the light higher above the tire, and so reduces the shadow from the tire. And when your front tire is 2.3" wide, that matters!

If you do this, you must make sure that the yoke is far enough below the mount that as the brake pads get thinner with wear, and the yoke moves further up during braking, the yoke never touches the mount. If the yoke contacts the mount, you'll lose braking force, and then you'll crash and die! Well, let's hope not. ;-) So, if every dozen rides or so you do a visual inspection of the yoke position while squeezing the brake lever, you'll know if it's time to change the brake pads or make other brake adjustments, such as shortening the yoke cable.

If my bike had wide profile cantilever brakes, the yoke could be positioned above this mount. But the brakes on this bike are low profile, at that requires a low yoke position.



This photo shows the beam of a prototype IQ-X. I'll have photos of the production version's beam as soon as possible.

I've now ridden with the IQ-X, and compared it with the Cyo Premium headlight. The beam is noticeably brighter at moderate speeds, it's also wider, and has better concentration of light at the top of the beam, making it a bit better for fast descents. It's a wonderful headlight. I can't say if the beam is noticeably brighter overall at high speeds, as I haven't yet been able to do a high speed comparison. But I can say that I don't think the major reason for choosing the IQ-X over the Cyo or Luxos B should be the higher lux rating, but rather the better distribution of light. I'll have more to say about this once I've spent more time riding with it.

Compatibility - Safety Issue!

We have recently discovered, (April 19, 2017) that the IQ-X headlight and the Busch & Müller USB-WERK charger are not compatible. When the cache battery in the USB-WERK is charging, the IQ-X beam becomes quite dim. While riding, this can happen for about two seconds, every thirty seconds or so, and so causes a dangerous situation, since the rider will briefly not be able to see the road ahead. If you have the USB-WERK and plan to use the IQ-X headlight, you should be prepared to unplug the USB-WERK at night. I recommend using the Lumotec IQ CYO Premium T Senso Plus or the new IQ-XS with the USB-WERK, since they are unaffected by this.

Some other headlights can also become dim when used with the USB-WERK, but only by very small amounts, so you would barely notice this while riding, so there is no safety concern.

Busch & Müller IQ-X, Silver, Part # B&M164RTSNDi, Price: $ 160.00

Busch & Müller IQ-X, Black, Part # B&M164RTSNDi-01, Price: $ 160.00

If you damage the mounting band, we sell replacements.

Busch & Müller mounting band for IQ-X headlight. Part # B&M464SCHELLE/PB, Price: $ 11.00

If you have the IQ-X and want to charge your mobile phone or GPS device while you ride, I recommend the E-WERK from Busch & Müller, or the Plug III from Tout Terrain.

New for 2014, Eyc, Cyo and Fly Headlights


The Lumotec Eyc, pronounced like "bike" (also like "like" for that matter) is very small and light; only 70 grams without the mount. The Lumotec T Senso Plus version with "Licht 24" daytime running lights, automatic switching and standlight. The switch has two positions, Senso and Off. When in Senso mode, the light automatically adjusts between Daytime Running Light mode in daylight, and the primary LED for road illumination at night. The Lumotec Eyc N Plus, a less expensive version with just the on/off switch and standlight but no daytime running lights is also available.


Yup, it's really small. The beam is almost as bright as the Cyo at 50 lux, compared with 60 lux for the Cyo. It's also a slightly narrower beam than the original Cyo headlight. In use, you probably wouldn't notice the difference in width, it's that small a difference. It's ideal for the urban commuter who primarily needs to see potholes and be seen by others. The IQ2 optics gives you good visibility at a distance, but also excellent near-field illumination of the road ahead. I photographed the beam October 27, 2013.

beam photo

I'm very impressed by this headlight. I've ridden with it and I like it a lot. For riding at moderate speeds, 15mph and below, it's as good as any other headlight I've ever seen. It's only at higher speeds during steep descents, and then only on roads that are otherwise unlit that this headlight falls short of other headlights costing much more, like the IQ Cyo Premium or IQ-X. Those more expensive headlights have wider beams at a distance and are a bit brighter at a distance. But for the urban commuter this headlight is gob-smackin' good.

To put this in perspective, only a few years ago, a bicycle headlight this good was unheard of. If I'd had them then, I could have sold truck loads at $300 each.

Eyc beam

This beam image was provided by Busch & Müller.

In my opinion, the "T" version is the one to get. Leave it on all the time and you'll have a nice daytime running light during the day, and the beam will automatically change to illuminate the road ahead when it gets dark, without blinding oncoming drivers. And, your taillight will be on as well, day and night.

Lumotec Eyc T Senso Plus, Part # B&M160RTSNDi-04, Price: $ 83.00

Lumotec Eyc N Plus, Part # B&M160RNDi-04, Price: $ 75.00

Eyc headlights ship without a taillight wire. We sell them separately.

Lumotec IQ Premium Cyo



The Lumotec IQ Cyo headlights have gotten an upgrade! The two new versions are called Lumotec IQ Premium Cyo, and have a even wider beam, about twice the width of the original CYO, improved near-field road illumination with a more even distribution of light from near to far on the road, and revised switches. I have ridden my bike with the new optics (a prototype) and I'm very impressed. On our narrow back roads here in Hillsborough, the original IQ optics didn't give me much light off to the side of the road. That never really bothered me as the illumination of the road itself was so good. But now that I'm riding with the new optics, I'd hate to go back.

I should say that when riding through the center of town, which has overhead street lights, there's no significant difference. But as soon as I get on those back roads, I feel more confident, particularly on fast descents. These headlights are amazing.

The IQ Premium beam is not quite as wide as the Luxos beam, and is perhaps not quite as good on a very fast descent, but it's awfully close, for a lot less money.

I'm stocking both versions of the IQ Premium CYO; the version with Daytime Running Lights (Licht 24), IQ Premium CYO T Senso Plus, and the less expensive version without Licht 24, IQ Premium CYO Senso Plus. Both versions have a 2 position switch. Off & Senso.

First I'll describe the "T" version. In Senso mode riding in daylight, the Daytime Running Lights are at full brightness. At dusk, the headlight will automatically switch over to nighttime mode and the Daytime LEDs will dim down so the road can be fully illuminated by the main LED which runs at full brightness. Or you may switch it off entirely.

The IQ Premium CYO Senso Plus can also be switched off entirely. Or, in Senso mode it will switch itself off during daylight and automatically switch itself on when it gets dark.


Busch & Müller Lumotec IQ Premium Cyo T Senso Plus, 80 lux, Part # B&M1752QTSNDi,
Price: $ 113.00 (Includes a taillight wire)

Busch & Müller Lumotec IQ Premium Cyo Senso Plus, 80 lux, Part # B&M1752QSNDi-04,
Price: $ 106.00 (Includes a taillight wire)

Note: Busch & Müller also makes the IQ Premium CYO RT Senso Plus for the German market. It has a reflector built into the front glass cover. The reflector is required by law in Germany. But no cop will ever haul you off to the slammer for having a front light but no reflector here in the US or Canada; and since the reflector makes the RT version a bit dimmer, I don't import that version.

Lumotec IQ Premium Fly RT Senso Plus


In my opinion, this is the best all around headlight for the daily commuter. I don't say this because the nighttime driving light is the best. It isn't. But it's so close that it's almost impossible to see the difference. However, the Daytime Runing Lights (Licht 24) in the IQ Premium Fly RT are better than any other dynamo headlight, including the new Luxos U, shown below. It's better because the six daytime LEDs, being spread over a large area, make for a very noticeable light during the day, increasing your visibility to oncoming drivers. The IQ Premium Fly RT's Licht 14 LEDs are spread over a larger area than the other Licht 24 headlights, and are therefore easier for oncoming drivers to see. We've all had the experience of an oncoming car driver turning left directly in front of us. Now, the driver won't be able to tell the judge he didn't see you. Of course, the whole system can be switched off if you like, but since the drag from dynamo powered lights is so low, why would you?

The daytime running light LEDs are dimmed at night when the primary LED is lit up at full intensity, illuminating the road surface ahead of you. The beam shape of the primary LED is the same as the beam in the Lumotec IQ Premium CYO headlight. The daytime LEDs remain lit at night just enough to help with reading roadside signs, and present a larger "footprint" of the headlight itself to oncoming drivers, but not bright enough to blind oncoming drivers. If the daytime running lights were as bright at night as they are in the daytime, they would tend to blind oncoming drivers.

Now with a two position switch; Off/Senso. In Senso mode riding in daylight, the Daytime Running Lights are at full brightness. At dusk, the headlight will automatically switch over to nighttime mode and the Daytime LEDs will dim down so the road can be fully illuminated.

Busch & Müller Lumotec IQ Premium Fly RT Senso Plus, 60 lux, Part # B&M1742QRTSNDi,
Price: $ 98.00
(Includes a taillight wire)

Fly Cantilever Mount, part number B&M474DUPB: $ 5.50

Lumotec Avy


This new headlight replaces the Lumotec LYT. It has better optics, similar in design to the CYO and Eyc. It's smaller and less expensive than the Lumotec Lyt, so I am no longer stocking the Lumotec Lyt. Good side illumination for added safety. 30 lux


Two versions. "N Plus" with On/Off switch and standlight. And T Senso Plus with Daytime running lights (Licht 24) and automatic switching between daytime beam and nighttime beam. Mount included, as shown.

B&M Lumotec Avy T Senso Plus, Part # B&M162RTSNDi-04, Price: $ 67.00

B&M Lumotec Avy N Plus, Part # B&M162RNDi-04, Price: $ 51.00

beam image


The new for 2018 Upp headlight provides a 30 lux beam with excellent near-field illumination ideal for the urban commuter. The included mount works with any unicrown fork with either disc brakes or v brakes. Available in two versions. The Upp T Senso Plus will automatically switch from a daytime beam to a nighttime beam as ambiant light levels rise or fall. The less expensive Upp N Plus is manually operated; either on with a nighttime beam or off.

Busch & Müller Upp T Senso Plus, Part Number B&M166TSNDi, Price: $ 39.00

Busch & Müller Upp N Plus, Part Number B&M166NDi, Price: $ 32.00

Lumotec Classic


New for 2012, the Lumotec Classic is styled much like the dynamo headlights of the 1950s. But the internals are all modern, using the LED, optical system and electronics of the Lumotec Lyt headlights. As with the other B&M headlights, it's available in two versions. All have Standlight technology. The LED remains lit, at a lower intensity for several minutes after you stop, say at a traffic light. I also stock a version with "Licht 24", Daytime Running Lights.

headlight switch

Here you see the top mounted switch. This is the switch label used on the daytime running light version. The "N" version has different labeling, but the same switch. Both versions ship with a fork crown mount that's suitable for caliper brakes, disc brakes or V brakes. If you have cantilever brakes, you can use the same cantilever mount as the Lumotec Fly and Lumotec IQ Fly.

The Lumotec Classic headlights can be used with or without a 6 volt wired taillight.

25 LUX

B&M Lumotec Classic N Plus has a 2 position On/Off switch, and of course, a standlight.
Lumotec Classic N Plus, part # B&M1786CNDi: $ 63.00

B&M Lumotec Classic T Senso Plus has a 3 position switch, On/Off/Senso; "Licht 24" Daytime Running Lights, and a standlight.
Lumotec Classic T Senso Plus, part # B&M1786CTSNDi: $ 75.00

B&M Fly Cantilever Mount, part # B&M474DUPB: $ 5.50


This beam image provided by Busch & Müller.

Lyt Basic N Plus

This headlight produces 20 lux and has the same shape of beam as the Classic.

B&M Lumotec LYT Basic N Plus, Part # B&M B&M1781NDi, Price: $ 34.50

Onefive T Senso Plus


This new headlight, as of 2016, is made exclusively for 1.5 watt dynamo hubs. It must not be used with 2.4 watt or 3 watt dynamos, as those higher power dynamos will damage the Onefive. But if you have been sold one of these low power hubs, the Onefive T Senso Plus will provide a brighter beam than a headlight designed for a 3 watt hub.

As of March, 2016, the only 1.5 watt hub I know of is the Shimano DH-S701.

Busch & Müller Onefive T Senso Plus, Part # B&M165RTSNDi, Price: $ 62.00

Unswitched Headlights

The headlights for tire driven dynamos like the Busch & Müller Dymotec 6, Dymotec S12 and others do not require a switch since the system is turned on by moving the dynamo into contact with the tire. By the way, it's that movement that determines whether a sidewall dynamo is right sided or left sided. So the more expensive switched headlights that I sell for hub dynamos are not needed. I stock all of the 6 volt halogen and LED headlights that Busch & Müller makes for use with the Dymotec 6 and (discontinued S6) generators, or any 6 volt tire driven generator. I stock a 12 volt headlight and a 12 volt rack mounted taillight for use with the Dymotec S12. I also stock spare 5 watt bulbs for the headlight.

All of the headlights I sell have circuitry to protect the bulb from burn-out at high speeds. All 6 volt halogen headlights ship to me with a 2.4 watt bulb installed, and are intended to be used with a .6 watt taillight. A 3 watt bulb is optional for the 6 volt headlights when used without a taillight. The 12 volt headlight ships with a 5 watt bulb. 5 watt bulbs cannot be used in a 6 volt headlight. 2.4 or 3 watt bulbs cannot be used in a 12 volt headlight. All current LED headlights can be used with or without a taillight attached.

It's important to remember that Busch & Müller uses the same housings for headlights intended for tire driven dynamos as they use for headlights intended for hub dynamos. So, when you receive a headlight for use with your Dymotec 6 sidewall dynamo, it may well have a switch, but the switch has no function. Some headlights for hub dynamos have extra LEDs for daytime running lights. So you may see where these LEDs are missing. But this is OK as headlights for tire driven dynamos don't have daytime running lights.

Busch & Müller Lumotec Eyc Plus


This photo is of the hub dynamo version. The Eyc Plus looks identical. Only visual difference is the name on the side. And, if you will always ride with the headlight on, you can save money buying this unswitched version.

This is by far the best headlight available for the Dymotec 6 dynamo. See the photo of the beam.


Notice how evenly the road is illuminated, from just a couple of feet ahead of the bike out to about 150 feet ahead. Only a few years ago, there were no bicycle headlights at any price with a beam this bright, this wide, and this even.

Busch & Müller Lumotec Eyc Plus, Part # B&M160RDi, Price $ 62.00

If you have a 6 volt sidewall dynamo lighting system on your bike, and you're thinking that you have to upgrade to a hub dynamo to get a better headlight beam, you're mistaken.

The Eyc Plus is not compatible with the older and now discontinued Dymotec S6 dynamo. But it is fully compatible with the Dymotec 6 dynamo.

Busch & Müller Lumotec Oval Plus 12

Lumotec Plus


Busch & Müller Lumotec Oval Plus 12 (12 volt, 5 watt) headlight and brackets for use only with, now discontinued, Dymotec S12 generators. Comes with single strand 185cm wire and connectors. Comes with a 5 watt bulb. Available now: $ 77.00

A reflector is above the lens for added safety.

The bracket shown will mount the light directly over the front tire using the hole in the center of the fork crown on bikes with cantilever brakes or v-brakes. Also included with the Oval headlight is a bracket for mounting on bikes with caliper brakes. These brackets are also sold separately.

Replacement Halogen Bulbs

All Busch & Müller halogen headlights use HS3 drop in style bulbs, made by either Osram or Phillips. Almost all of the headlights I sell these days use LEDs. These bulbs are only for use with older halogen bulb headlights.


They don't screw in, they drop in. Notice the flange around the center of the bulb. See the notch in the flange? That notch fits around a ridge in the bulb mounting position of the headlight. The filament is positioned relative to the notch. So the notch is forcing the filament to be aligned very precisely and that is critical in focusing the beam correctly.

That's why Busch & Müller uses these bulbs rather than bulbs that screw in.

These bulbs are available in two versions; one version is for use when the headlight is being used along with a wired taillight. The taillight consumes .6 watts. The total draw on the dynamo needs to be 3 watts. So with a .6 watt taillight, you use a 2.4 watt bulb.

If you can't use a wired taillight for some reason, you would then use a 3 watt bulb in the headlight. If you use a 2.4 watt bulb in the headlight when you don't have a taillight connected, the bulb can burn out quickly.

6 volt, 2.4 watt halogen bulb: $ 4.00

6 volt, 3 watt halogen bulb: $ 5.00

These 6 volt bulbs work in all Busch & Müller 6 volt halogen headlights. They also work in the Schmidt E6 as well as the old BiSy headlight.

12 volt, 5 watt halogen bulb: $ 16.00 (The 5 watt bulb can only be used in the 12 volt Lumotec Oval Plus 12 headlight.)

I don't sell other types of bulbs for dynamo headlights. I only sell bulbs for the headlights I sell. If you have a dynamo headlight with a screw in bulb, my best advice is to replace it with a Busch & Müller headlight. The beam will be much better.

I do not sell bulbs for taillights. Since LEDs work so much better in a taillight than bulbs, I recommend that anyone with a bulb type taillight upgrade to an LED type. See here for dynamo powered taillights.

Mounting Headlights

All Busch & Müller dynamo powered headlights are designed to be used in all weather. Your bike can sit out all day in the rain, and it can be raining hard while you ride, but it won't effect the proper functioning of the headlight, provided that the headlight is not being sprayed with water. Huh? I'll explain.

For example, if you mount the headlight at the crown of the fork using a Busch & Müller mount, the light will be high enough above the front tire that water won't spray up from the tire and hit the light. And of course any suitable commuting or brevet bike will have fenders. But some bikes are now being made by custom frame builders with special front racks which have headlight mounts towards the front of the rack. In some cases, the headlight is right in the path of water being sprayed towards the front. Busch & Müller dynamo headlights all have openings at the bottom to allow any water that gets inside to drain out. But water spraying off a tire can enter via those openings. So you must position the light where it won't be subjected to this type of spray. If you must position the light well forward of the front tire you must also place a barrier of some sort to deflect water away from the headlight.

If you can't mount the headlight at the fork crown because you have a bag in the way, you can often mount the headlight at the side of the fork, just below the tire. Along the fork blade, the headlight will only get water from above, which won't cause any trouble. See my mounting page for more info.

Where to Buy?

Call us at 603 478 0900 to order directly from Peter White Cycles.

See this page for a list of local bicycle shops that generally stock our products, or can order them for you.

See this page about ordering from us.

Dealer Inquiries Invited. Please call 603 478 0900

If you have a retail bicycle shop, or are a bicycle manufacturer, you can purchase Busch & Müller products, including dynamos, headlights, taillights, battery lights and mirrors at wholesale prices for resale. Any shop in the US or Canada can purchase Busch & Müller products for sale in your store. Please call me for pricing. Peter White Cycles is an official representative for Busch & Müller in the US and Canada, and we want all bicycle shops to be able to sell these products.

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This page updated: Saturday, September 22, 2018

Peter White Cycles LLC
24 Hall Rd.
Hillsborough, NH 03244
603 478 0900 Phone
603 478 0902 Phax