The Shocking Truth, Part 8: Penultimately Speaking

I say penultimately because everything is provisional. Lights are improving, and I expect dynamos/generators to improve as well.  It’s getting better all the time!

But life is all about tradeoffs. Having eliminated (for most purposes) the bugaboo of generators slipping in the rain (by “rain” I mean what most of us are willing to ride in, not monsoon conditions), we are left with the following items:

· Power

· Weight

· Noise/Vibration

· Subjective resistance

· Aesthetics

· Cost

Now, to rate each of the dynamos on these factors. I will give each a “+” if it did subjectively better (my subjectivity) in a given category; a “0” if was middle of the road, and a “-“ if its performance was sub-par. Then I’ll give a very quick set of comments for each unit.

Hub Dynamo:

Power Weight Noise/ Vibration Subjective Resistance Aesthetics Cost
+ + + 0

If you want to feel like you’re riding on top of a laser, nothing beats a hub dynamo. You have instant-on lights and plenty of juice. But they’re heavy and costly: they add significant weight to a bike, and you’re going to have to have a new wheel built. Many feel that the oversized front hubs required are ugly—I don’t think so, but they’re not especially pretty, either. On the other hand, there is practically no noise or vibration when you are using these hubs, lights off or on. Before I started on this project, I would have said that even when the lights are on, the resistance is undetectable. I’m much less certain of that now. It’s only a few watts with the lights on, and very little indeed with them off, but yes, I think I can feel the difference (with the lights on).

For me, these tradeoffs are worth it. Simply to know that I can be seen at the flick of a switch isa reassuring, and the weight doesn’t bother me. For anyone who rides in all weather conditions and needs their lights to absolutely work in spite of what Mother Nature puts out, the dynohub remains top choice.

Bottle Dynamo:

Power Weight Noise/ Vibration Subjective Resistance Aesthetics Cost
0 0 0 +

As an inexpensive, inexhaustible source of power, the bottle is hard to beat, which may explain its survival in multiple forms after many years of battery domination. It puts out adequate power for the 3W StVZO standard, and while it may be more noisy than some of the alternatives, it wins on a cost basis. Beware of paying too little, however, as some bottles are more cheaply constructed than others. The look is utilitarian, but the unit is clearly an add-on, something that might tempt thoughtlessly destructive people to make it a wrench-off.

Traditionally, these dynamos mounted to the rear wheel. Had I been able to do that with my frame, I might have found the idea more appealing. As it was, I found a front-mounted bottle to be noisy, though redirecting it to the rim (rather than the sidewall) reduced this issue. This can be done with dynamos equipped with rubber rollers; those with metallic rollers present an additional risk to lightweight sidewalls.

Bottom Bracket Dynamo:

Power Weight Noise/ Vibration Subjective Resistance Aesthetics Cost
0 0 0 + 0

The worst thing about the bottom bracket unit is that it is no longer being produced. While its power and weight are on a par with that of the bottle, its location low on the bike helps reduce noise and vibration, and while it produces some resistance from rubbing on the tire tread, it is practically invisible. If I wanted to light a classic bike, and the classic aesthetic didn’t include something like a Soubitez bottle, this would among my top choices.

While the bottom bracket unit benefits from its location, it can be comparatively difficult to find (due to its arguable obsolescence). But this should not remove it from your consideration. My first dynamo was a bottom bracket model, and it was a revelation to finally have light whenever and for as long as I wanted it. If you’re up against financially, you may find one of these for cheap—certainly, cost-wise it is at least on a part with a decent bottle.

Velogical Rim Dynamo (Trekking Model):

Power Weight Noise/ Vibration Subjective Resistance Aesthetics Cost
+ + + +

The Velogical is amazing; although it is only rated at the 1.5W StVZO standard, it is capable of supplying lights and a USB charger at the same time. It weighs—well, it weighs very little, runs smoothly on the rim (thanks to the O-ring) and feels like it adds very little in the way of load to the bike. It’s attractive while being compact enough not to look like an add-on (many will look at a bike and simply miss the Velogical altogether if they’re not looking for a rim dynamo). It’s unlikely to be a target for vandalism or theft.

Its primary weaknesses are its comparatively low power output, its cost (which may price it out of the range of commuters, but which should be understood as not requiring a special wheel), and its very-low-speed performance. As to the last, Velogical Engineering, after reviewing my review, suggested that the dynamo could be reversed on its mount (something I should have thought of, but didn’t). Since the wire handle on which the dynamo is mounted passes through its base to one side of the center of rotation, reversing the dynamo on the wire (easily accomplished with a grub screw) allows you to increase pressure and so improve low-speed performance—something I did not account for in my review. Here’s a photo that illustrates this improved position:


Note that the dynamo has been reversed, so that the wires come out at the far side. Note also the use of a thicker O-ring and the very clever way in which the wires are passed through some of the extra holes in the mount—which should prevent the kind of damage I was worried about. Overall, these modifications should deal with some of my concerns with this unit.



Dynamo Power Weight Noise/ Vibration Subjective Resistance Aesthetics Cost
Hub: + + + 0
Bottle: 0 0 0 +
B. Bracket 0 0 0 + 0
Velogical + + + +

OK. So, time for some recommendations. If it’s absolute power you want, and you’re willing to pay the price (which is not inconsiderable) nothing is going to beat the hub dynamo. Riders who spend a lot of time out in the dark, in bad weather, who need their lights, really need look no further. But if weight is a concern, you need not look here. Fortunately, for most of the riders in the categories I’ve described, weight will not a deterrent—their bikes are already loaded for bear. But for some randonneurs, weight and daytime resistance may militate against the hub.

Typical commuters would be well served by either the bottle or bottom bracket model. In fact, the bottom bracket unit is likely more survivable, in spite of its location in the nastier elements of the road. It’s less likely to attract attention, and it can run on the tread of smooth-ish tires. Therein likes the rub; tires with external treat (i.e., MTB tires) will not work with the bottom bracket model. For such uses, the bottle is superior, especially if it can be run on the rim rather than the tire sidewall. The cost is low, but the price to be paid comes in noise and vibration (and likely because of that noise and vibration, a heightened sense of resistance—though by no means of the Bart Simpson level). Nevertheless, both the bottle and the bottom bracket dynamos promise power unlimited by battery life—and both can be completely removed from the resistance equation when not needed. These are the daily commuter’s tools of choice.

Finally, if weight is at all an issue, and if cost is not, the Velogical promises phenomenal cosmic power (OK, perhaps not quite in magnitude, but certainly in duration) in an itty-bitty living space (I do miss Robin Williams). If you race and occasionally find yourself out after dark; if you are a randonneur of the minimalist, high-speed, carbon frame school; if you simply want an excellent source of light without needing to dedicate a wheelset to that cause, the Velogical is your dynamo of choice. With modern LED lighting, its lower output power does not present a serious problem, and only its cost may serve to keep it out of the hands of more riders.

A Closing Note

I have enjoyed tremendously the opportunity to test these various units. If you’re interested in learning more about dynamo lighting systems, let me recommend typing some of the terms used in the evaluations I’ve done (both this article and early Shocking Truths) into your favorite search engine. There are decades of experience out there, and much (though by no means all) of the past 20 years is preserved on the net.

I encourage readers to add comments to this site, particularly at the end of this post, linking to other articles, disputing my findings, correcting my mistakes, offering to send money ;-), etc. I am a cyclist. I ride (occasionally) in spandex and (often) wearing a Styrofoam hat. I have no dignity!

Herewith, I conclude my major—though probably not last, you poor souls—writing project on dynamo lights. I’ll be seeing you, well lit, on the road!

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16 Responses to The Shocking Truth, Part 8: Penultimately Speaking

  1. judge3690 says:

    Great overview; I’ve been following this series with interest, especially having made the decision to switch to dynamo lighting.

    I went with a Shimano Alfine DH-S501 black dynohub (Centerlock disc brake mount), powering a Busch and Müller Luxos-U headlight (and a B&M Toplight Line Plus in the near future). As a transportation cyclist—no car—and a relatively heavy utility bike, I don’t notice the weight or active resistance, except to help balance the rather heavy rear end. In fact, when I have the lights on, pick up the front end and give the wheel a spin, it spins freely for a long time, just like a regular hub. I do notice, though, that the front wheel seems a bit more prone to shifting slightly in its quick-release slots under heavy front braking, possibly a combination of disc brakes and the heavier hub. I do like that it gives plenty of power, even with my 700c wheels, to power the light at full night brightness and charge my phone, and I can even use its floodlight mode for a while without losing charging current.

    • I haven’t used disc brakes, but it’s my understanding from rumor and discussion I’ve heard that movement in the axle area under heavy braking is not unknown with discs; I’ve had absolutely no issue with this in approximately ten years with my Shimano dynohub and rim brakes, so I think that it’s more likely you’re seeing a braking phenomenon than a dynohub phenomenon.

      While it’s outside the scope of what I’ve been working on here, I’d urge you to check with your LBS and research the slippage a bit–it sounds a bit scary to me!…indeed, a quick search turns up this page, which may be what I’m remembering:

  2. Chad Knutson says:

    Thanks for doing this review. I’d be very interested to hear your thoughts if/when you get a chance to try Shimano’s (or another brand if it becomes available) 1.5W dynohub, It seems that this is not a high quality unit (judging by the $40 price). Upgrading the internals to match the engineering of Velogical has some serious potential. It could be low weight, have excellent performance, and not waste energy (I’m not interested in charging gadgets via USB).

    • I’m very interested in the “low power” Shimano (and, as you mention, potentially other) dynohubs. Given developments in LED lighting, I wouldn’t be at all surprised if these became popular in the US market, but we shall have to see. I will say that the overall construction of the Velogical is remarkable, and that this kind of construction is likely not to become available in an inexpensive hub dynamo, which is too bad.

      The really interesting thing, though, is that the distinctions between all of these devices are really fairly marginal. Back when you needed to heat a filament and lights were, essentially, “dumb” devices, the differences were more important. In an age of capacitor-run standlights and decreasing power requirements, any one of these dynamos does a fine job.

      I’ll stick with my old “3W” hub generator for now, though. I like to think I have enough juice between that and my eDelux to light up the road pretty well!

  3. Philip says:

    Very cool article! The Velogical unit was a revelation; I hadn’t seen that before. I will read the previous articles in the series.

    I did have a comprehension issue with your charts, having to mentally translate the pluses from “more than” to “better than.” To me, a + under “weight” reads as “more weighty,” not “more better in regards to weight,. What should be a quick comparison becomes a four or five step process: “oh. huh. no. right. reread.”
    Using different symbols, a 0-10 number scale, or recasting the labels as positive attributes (“lightness” instead of “weight,” for instance) would have helped me understand the charts more quickly.

    Sorry for the dissertation on presentation instead of information! The information was quite good.

    • You’re right. My initial intent was to go with a primary school grading system–E for excellent, S for satisfactory, P for poor. I decided to abandon that system because we’re really looking at the margins here. Just about everything could be graded in terms of A+, A, or A-. With that limited range of variation, I felt using the E/S/P system would be inapt. Happily, all dynamos made the grade!

      I may have to redo the charts at some point, though, as you make a valid criticism.

  4. Craig says:

    What a blast! This whole series was really fun to read even though a good chunk of it was already in my knowledge base, having ridden and still riding every system mentioned except the Velogical (I’m getting one). BUT (and this is a big butt), I do have to take issue with your view on the aesthetics of the bottle generator (everybody’s got an opinion along with something else). There is just something Retrosensual about this gizmo attached to your bike, a “high tech” appendage oozing with tradition and drawing the attention of the uninitiated. “Hey dude, what’s that gizmo there?” “It makes its own electricity so you can ride into the night!” “Whoa! Really?” For me, the buzzing is a mantra massaging mind and soul as you slip thru the dark. And then, combine it with the meditative “tick tick tick” of a Sturmey Archer hubgear and, oh my gawd, you’re in Nirvana. I find myself breaking into a cold sweat and experiencing shudders of delight…of course, maybe that’s the result of pushing against the double resistance of bottle generator and a “friction box” SA hubgear. In any case, good articles. Thanks.

    • Thanks for your comments. I can fully understand your view of the bottle–I once owned a gorgeous chromed Soubitez–but I think they’re the most obvious of the generators and–consequently–the most likely to fall victim to casual mistreatment.

      I also suspect that most of my unlike (and it’s really marginal; it’s not that I dislike bottles from an aesthetic perspective, it’s just that I like the others slightly better) has to do with lousy mounting systems. Many of these look like they were built from Erector Sets at best, scrap metal at worst. But I have seen European bikes with excellent bottle dynamo mounts, and those are something different. As are some of the constructeur/porteur/randonneur frames I’ve seen, where the bottle is snugged up to the tire by a lever and cable assembly.

      They certainly do work, and if they’re to your taste, more power to you!

      • Craig says:

        My bottle generator is mounted on a 1969 Jack Taylor with a bottle generator mount. It does make a difference in looks and ease of mounting/operation.

  5. Scouter John says:

    The only reason I stopped using a bottle generator (which was the only effective option for a cash-strapped kid, back in the fifties – and I emphasize the cash-strapped bit!) was that, when I got out here to the “wet-coast”, my options were: ride in rain (and often monsoon conditions, with just a hint of open-sea frazil thrown in for excitement) or hang it up. The possibility of riding all 14 months of the year was far too attractive for the latter, as I’d grown up, bitterly resenting having to stow the bike from late-November to April 1 (I lived in the Ottawa Valley at the time.)
    I found that the bottle dynamo, no matter what I did, tended to crap out just when I needed it most – commuting in west-coast winter storms in the dusk – and it WAS always dusk both ways. I came across, tried, and liked a BB dynamo – it fit well, and – more important, it always produced.
    A change of frame, when the one that dynamo was on died (and it was not an expensive or particularly good frame – the build-up was, by the time I retired it, far more valuable than the frame itself) meant that the BB dynamo had to be retired, as no longer fitting. About that same time, the first LED tail lights came available at prices that I could afford (or would, probably rather) and a very neat halogen light, with a 6-V SLA battery was also available, at a price I was willing to pay. When the halogen unit died – switches and other components wore out simultaneously – did a “one-horse shay” on my – I was able to replace it with a Philips SafeRide, battery operated, that both fit my needs, and has provided loads of light.
    At the moment, I’d only consider changing, if I were to be able to build a lighting suite – that contained clearance lights, head, tail, brake and turn functions, when I’d want a hub to boot a small battery pack.
    One thing is that I ride with lights on, even in the day – if lights help make cars and trucks more visible on the road, it seems to me that, *a fortiori*, they would be good for myself – particularly when all my experience is in dealing with motor traffic on their own turf and terms.

    • After I was hit a couple of years ago, I, too, decided to leave my lights on during the day–one of the reasons I prefer dynamo lights, since there is no incremental cost (either battery replacement or the need to remember to charge the system).

      As for your suite, I have played with the idea of brake lights, using a microswitch on the rear brake cable. It worked OK, but at the comparatively low power levels we’re talking about, I decided it wasn’t likely to make too much of a difference. Similarly, turn signals are a problem on a bicycle because there isn’t enough width to make their meaning apparent. Even motorcycles often use stalks to move their turn signals farther out from their center, and motos are generally wider to start with. Certainly, the commercial turn signals I’ve seen for bicycles are little more than toys. A signal built into the back of a cycling glove, and that activated only when held at a certain angle, might work better…

  6. Mikko Heiska says:

    Hello, nice post!

    I would like to introduce you to “Magnic Light” ( if you have yet to hear about it.
    It’s revolutionary compared to traditional bike dynamo lightning, fundamentally being a contactless dynamo utilising a form of electromagnetic technology.

    I would be most interested to hear your thoughts on it.

    Best of luck at your adventures,


    • Thanks! I’m familiar with Magnic, but didn’t include Magnic’s stuff in this series because I wanted to focus on generation capabilities–consequently, all of the dynamos I used here were run with the same lighting system (An eDelux [version 1] and a Pixeo). The Magnics that are currently available look interesting, but have their own, built-in lights, and so would have to be evaluated on a different basis.

      I’m certainly intrigued by them, though.

      • Mikko Heiska says:

        I see. Nonetheless, I’m glad you have done some research considering them!
        They do look like a lightning system that’s worth trying once I equip myself with the new bike I’ve been searching for.

        Thank you for your opinion.


      • I have a friend who was waiting for the new ones to come in, and hope to see him in a couple of weeks at a bike to work breakfast, so I’ll inquire then. I did speak to one user who said they were good, but nowhere near as bright as the eDelux. My friend and I will have to do a night ride to evaluate the new models!

  7. Pingback: Longer term with the Velogical Rim Dynamo | Law School is So Over

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