What You Need to Know About Dynamo Lighting

Dynamo lighting is reliable, durable, environmentally friendly, more difficult to steal, and extremely convenient.

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GOODY_Dynamo_Riv-Son-Light-Photo-David-Niddrie-9082 - RESIZED

Photo by David Niddrie

Dynamo lighting is reliable, durable, environmentally friendly, more difficult to steal, and extremely convenient. Having lights permanently mounted on and powered by your bicycle means you’ll always be well lit.

What is a dynamo?

A dynamo is an energy-generating hub built into the front wheel of a bicycle that typically powers lights. Dynamos can also power USB ports and all manner of fun things, if you’re interested.

Early dynamos were tire-driven, resembling small bottles mounted to a bicycle’s fork and turned by the tire or rim as it moved past. Between World War I and II, English bicycle component manufacturer Sturmey Archer first popularized the Dynohub, moving the generator inside the hub of the front wheel. This alleviated inefficiencies of the tire-driven bottle dynamo, like premature tire wear, drag, and erratic engagement in wet conditions. Tire-driven bottle dynamos are still manufactured today, though most modern models are hub-based.

GOODY_Dynamo_Kissing-1_Photo-David-Niddrie-2315 - RESIZED

Photo by David Niddrie

What makes a good dynamo light?

A good light is bright enough to be visible, illuminates the road without blinding others, and stays bright while you’re stopped at a traffic light.

Most dynamo lighting equipment is designed to comply with German road-use regulations (StVZO/TA). These stringent and specific regulations are in place to ensure that cyclists are well lit from all directions and that the lights don’t interfere with other traffic.

A headlight should have a horizon, meaning that the light’s beam is limited by a hood at the top and aimed so that the center of the beam hits the ground 33 feet (10 meters) from the front of the bicycle. A concentrated beam illuminates hazards on darkened streets without blinding oncoming motorists and cyclists.

Lights are also required to have a standlight feature, a built-in capacitor that continues to power the lights for four minutes once you stop moving. This feature ensures that you remain visible while stopped at intersections.

In most countries, cyclists are required to have a white light up front and a red light in rear. A single dynamo can power both front and rear lights. Similarly bright battery-powered lights have run-times of only 1-3 hours before they require recharging.

Is dynamo lighting bright enough?

Dynamo systems offer plenty of light and can be tailored to suit different riding styles. When choosing a dynamo lighting system, you’ll need to consider both brightness and beam pattern.

Brightness is commonly described in two different units of measure: lumens and lux. While battery-powered lights are commonly rated in lumens, dynamo lights are more often rated in lux. Whereas lumens are a measure of the total amount of visible light emitted from a source, lux is a measure of the intensity of light in the usable portion of its beam pattern. This means that two lights with identical lumen ratings can have very different lux measurements, depending on how the light is focused.

Beam pattern selection will depend on how you ride. A fast rider covering a lot of ground will benefit from a bright light that projects further in front of the bike, giving ample time to react to hazards in the roadway. A rider travelling at a more leisurely pace will see the benefit of a light with nearfield reflectors, which better illuminate the area immediately in front of the bike. The night ride enthusiast will thrill at the brilliance of an unfocussed beam, evenly illuminating everything in front of the rider.

So why is dynamo lighting so rare in North America?

In many European countries, including Germany and the Netherlands, most bicycles designed for everyday use come equipped with dynamo lights. Bicycles have tabs for attaching tire-driven dynamos or come with hub dynamos right from the factory.

In North America, where recreation drives the majority of bicycle manufacturing and sales, lights are considered more of an accessory than a requirement. Your average bicycle shop will offer plenty of choices for battery-operated lights, often small and detachable, while dynamo systems may need to be special ordered. They can also be costly and require complex installation.

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Dynamo lighting is gaining in popularity in North America as more people are using bicycles for transportation. Manufacturers are starting to offer standard models equipped with on-board lights. For those looking to add them to their existing bike, dynamo hub and headlight combinations can start around $120 USD before installation. However, dynamo hubs require the assembly of a full wheel (spokes and rim) and will add labor and product costs. You can expect a typical dynamo build, including hub, lights, rim, and spokes, to cost from $220 for a basic set-up to $800 or more for high-end systems.

On-board lighting also adds some weight to the bike, typically 1.5-2 pounds (680-907 grams). While you wouldn’t want one on a race bike, you may want it on your winter trainer and you should certainly consider it for a daily commuter.

Why we love dynamo lighting.

The biggest advantage, from my wife’s perspective as she now refuses to ride a bike at night without dynamo lighting, is that one will feel safe. It’s bright, it’s always there, and it requires not much thought at all. No forgetting lights because you didn’t intend to be out after dark, no replacing or recharging batteries, plus an automatic on-switch.

Sealed from the elements, dynamos produce consistent and reliable lighting in all weather. A dynamo hub’s typical service life is similar to that of other bicycle hubs, meaning it will last you for many years. They are recyclable as scrap metal and do not contain hazardous chemicals.

Bolted to your frame, and useless without the generator, dynamo lights are far less desirable to thieves. After your initial costs you may even save money by no longer having to purchase new lights, batteries, or pay fines for forgetting your bicycle lights.

Traditional lights are a clip-on accessory for your bike. Dynamo systems make lighting an integral part of your bicycle. Can you imagine driving a car with strapped-on or half-charged lights?

Dynamo Lights are:

  • Safe. Dynamo lights are powerful and highly visible.
  • Convenient. Always with you. Always on.
  • Durable. Long-lasting LEDs.
  • Consistent. No half-charged or lost lights.
  • Sustainable. Reduce your environmental impact by freeing yourself from batteries.
  • Secure. Much more difficult for someone to steal.
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Momentum Mag would like to thank the generous support of Kissing Crows Cyclery for donating hours of their time building wheels and testing the product.

19 Comments

  • Thank you for this article, do you have any information/recommendations on hubs and power output. I am planning on taking a trip through Europe and want to be able to power phone/iPad as well as my lights. But do not know where to start with hub type or which brands are best. Thanks again for the article.

  • Gerald Smith

    I was just in Frankfurt, where there were a lot of bike commuters, and at least 95% had these dynamos. Surely they’re not all paying this much. Isn’t there a better price?

  • Amoeba

    The STVZO lights have sophisticated optics, similar in-effect to dipped car headlights, except the beam is intended to be directed downwards and straight ahead, not directed downwards and slightly to the right. The beam should be adjusted so that assuming level ground it strikes the ground about 10 metres / 33 feet ahead.
    http://swhs.home.xs4all.nl/fiets/tests/verlichting/index_en.html#licht-bundel-vorm

  • brizogg

    I used to train with an old school double bulb bike fitted with halogen bulbs on a dynamo and a fitted voltage regulator. at night, the beam was as bright as a motorcycle headlight on dark country roads – the best and cheapest source – when it was raining, I used to tie a thick rubber band around the rotor…

  • Joe

    My understanding of “horizon” differs from the author of this article, in that the farthest edge of the light cone should be 10m, putting the center of the cone (or bean, as he states it) a meter or two closer.

  • Russ

    I love the idea of the free power from a dynamo and the more powerful lighting I could run – but unfortunately I would fear for the life of my bike after investing in the front hub. As it sits currently, my 20+ yr old commuter flies under the RADAR, having a shiny dynamo hub and hard-wired lights would turn the wrong heads. If it was from home to office, fine – but doing errands and locking my bike up in front of the library etc… Can’t do it.

  • I started with battery powered lights and found two problems – making sure they are charged up when you unexpectedly get a chance to ride and they are often blindingly bright, making them less than safe when the driver headed towards you can’t see much at all, except the bright light. I now have dyno lighting on my commuter and road bike with the same headlight, the Busch and Mueller IQ CYO. The light is great for really dark country roads and I can see well enough at 20 MPH in those conditions. I also use daytime running lights during the day, commuting or on road rides. Unlike another commenter, I find them less useful in urban environments, where lights shining in my eyes makes my light slightly less useful. I now use a low power (Light and Motion Urban 350) set on low (75 lumens) aimed at the ground in front of me and hopefully not blinding oncoming traffic.

    As far as the brightness of being seen with dyno powered light, I find that they are fabulously bright in making others seen, even the less bright “be seen” on our local Hubway rentals. I recently saw a frequent commuter with his Busch and Mueller EYC 50 lux light and found it quite visible in low light conditions.

    I think people should consider dyno lighting. It is expensive as the article suggests. I spent about $500 on my commuter and $650 on my road bike (mostly a more expensive hub).

  • Ian

    Lux is not ‘a measure of intensity in the usable part of the beam’. It is a measure of intensity at one specific point, not at all the same thing, for example two lights with equal lux can have very different beam widths. Personally i find dynamo lights, and more generally lights built in compliance with the German regulations, adequate on well lit roads, and for being seen in most circumstances. But I so often ended up needing to supplement them on the wet, windy, hilly trips that are usual here (Highland Scotland ) that I’ve given up in favour of good battery lighting.

  • Wendell C

    +1 for consistency. This is by enlarge the biggest bonus. Remembering to charge battery power lights can be a bother day in and day out, especially if you commute longer distances. Battery lights also seem to fail more frequently. I have multiple battery lights fail, I have never had a modern dynamo light fail, even after 10 years of daily use. (I sometimes use both battery and dynamo lights coming down mountain passes at speed – under the same conditions battery lights have consistently proven less reliable).

    @Walter and @Mathew – On the subject of drag, it is mostly negligible, but differs by manufacturer, whether the light is on or off and your current speed. While the output is about 3W the drag is higher due to inefficiencies. The best dynohubs are about 60% efficient putting the total drag closer to 5W at about 28 kph (150 watts rider output). A baggy jacket or position on the bike will be a much bigger source of drag. The dynohub drag will be a little higher at faster speeds, but rider power will be multiplicatively higher (e.g. 375 watts @ 40 kph) so the drag relative to rider output power is actually lower.

    @Josh Williams (Author) – A minor technical error. The horizontal cut-off is done with mirror design not the hood on the top of the light. While a horizontal cutoff prevents *most* light from shining above the horizon, there is still some spill light. The hood on the top of the light is simply for the rider’s comfort.

  • Matthew

    @Walter: you can feel the drag spinning the wheel by hand (especially with a new hub, as it will have a bit of a “notchy” feel to it). But once you’re riding, there’s no sensation that you’re on a generator. For those who prefer numbers, a fully modern generator hub takes about 3W or so… your average cyclist can put out 150 watts no problem pedaling on flat land. So it’s about 2% harder to pedal than your current set up. That’s negligible to me, and the upside of having dyno lighting front and rear (plus having a USB charger for my bike gizmos while touring) more than makes up for it. The article is spot on… once you go dyno you’ll never want battery powered lights again.

  • WalterT

    Do the dynamos add noticeable drag? My only experience with modern lighting dynamos is with Capital Bikeshare, where the cycles are so tanklike that I can’t tell whether the power-generation is a factor.

    • allan carstensen

      a dynamo should give 3 watts and a good dynamo IE schmidt or the better shimano are more than 50% efficient, that means about 6 watts drag when engaged. The Schmidt drags about 1 watt when lights are off, shimano a bit more. Compare that with a normal commuters input of about 150watts. you can feel it but not much. i have about 15 yrs of using hubdynamoes on different bikes and really revomend it on any bike but your light racer.

  • Another +1 for dynamo lighting. When I give talks on All-Season Cycling I always talk about this option (while recognizing that for not-yet-everyday cyclists, the expense can be off-putting). Clever Cycles, mentioned by GeraldF below, has a pre-built dyno-hub wheel for US$120. With a basic front/rear light set, a full system can be had for about US$220 (+ any installation charge). While $220 is a lot right up front, it definitely pays for itself in my mind – I will lose, have stolen, or wear out that many dollars worth of removable light (& batteries) before I wear out the dyno set.
    Major bonus – always-on running lights for grey fall and winter morning/dusk hour rides.

  • GeraldF

    For anyone looking for a new bike that comes with front and rear dynamo lights pre-installed I highly recommend the Breezer Uptown 8. Clever Cycles in Portland sells it. It’s a utility bike with 8-speeds. It also comes with fenders, a rack, kickstand, full chain case and the rear wheel lock that’s common on European utility bikes. Once you try a dynamo light you’ll never want to go back to detachable lights.

  • Leif

    I love my dynamo set up. I feel a LOT safer with dynamo lights (as opposed to the “be seen” lights I had in the past) and it’s comforting to know that I will always be with light as soon as I start pedaling. Being that I’m a utility rider and always on my bike when I go out I am really appreciating the convenience that car owners have enjoyed for many decades – permanently installed lights day and night. A set up cost me approx. $500incl. hub, front and rear lights. and labour and wheel build. I would spend it again in a heartbeat.

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