FS: Dymotec 6 Generator NIB

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Eric Norris

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Nov 13, 2025, 8:45:56 PMNov 13
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I know there’s been some interest on this list for this item in the past, so …

Going through some of my bike paraphernalia a few days ago, and found a new-in-box B&M Dymotec 6 bottle generator. This is a classic, “bottle”-type generator that mounts to the frame and runs on the side of the tire to generate 6 volt/3 watt power. 

Peter White used to sell them—here is his archived page about the Dymotec 6:


Per Peter (and my experience), this will power modern 6-volt lights, with or without a taillight (max of 3 watts of power draw).IMG_0325.jpegIMG_0326.jpegIMG_0327.jpeg

The one I have is for mounting on the left side of the bike (it won’t work on the right side). The box has just the generator; you will need to supply the mounting hardware.

How about $45 shipped in the USA?

Let me know if you have any questions!

--Eric Norris
campyo...@me.com
Insta: @CampyOnlyGuy
YouTube: YouTube.com/CampyOnlyGuy 

Patrick Moore

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Nov 13, 2025, 9:10:51 PMNov 13
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Am I correct in thinking that the Dymotec has less drag than the old Union and Sanyo bottles? I thought of getting a Dymotec at one point but the bike it was to be used on never materialized.

FWIW, IME, even the old Union and Sanyo bottles weren’t horrible; not at all like the Bart Simpson clip. Basically you move to 1 tooth bigger in back, if even that — like a light headwind or very slight incline.

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Peter White

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Nov 14, 2025, 8:23:59 AMNov 14
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The Dymotec 6 was state of the art 25 years ago. If I remember correctly, the drag (if correctly aligned) was about twice the drag of the SON dynamo hub, which is extremely low. There was a higher spec version, the S6, which had even lower drag by somehow introducing negative feedback. The S6 was a fair bit more expensive. Then there was the S12, a 12 volt version which powered 12 volt lights.

Alignment is critical. If it's off by just a bit, the rubber roller will melt from the friction. So when aligning it, be sure that the axis of the dynamo intersects the axis of the hub.

PJW

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Eric Norris

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Nov 15, 2025, 7:53:49 PMNov 15
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Yes—lower drag but obviously more than a dyno hub. And a bit of a whining noise while it’s in operation. 

–Eric N


On Nov 14, 2025, at 5:23 AM, Peter White <peter...@gmail.com> wrote:


The Dymotec 6 was state of the art 25 years ago. If I remember correctly, the drag (if correctly aligned) was about twice the drag of the SON dynamo hub, which is extremely low. There was a higher spec version, the S6, which had even lower drag by somehow introducing negative feedback. The S6 was a fair bit more expensive. Then there was the S12, a 12 volt version which powered 12 volt lights.

Alignment is critical. If it's off by just a bit, the rubber roller will melt from the friction. So when aligning it, be sure that the axis of the dynamo intersects the axis of the hub.

PJW

On Thu, Nov 13, 2025 at 8:45 PM 'Eric Norris' via RBW Owners Bunch <rbw-owne...@googlegroups.com> wrote:
I know there’s been some interest on this list for this item in the past, so …

Going through some of my bike paraphernalia a few days ago, and found a new-in-box B&M Dymotec 6 bottle generator. This is a classic, “bottle”-type generator that mounts to the frame and runs on the side of the tire to generate 6 volt/3 watt power. 

Peter White used to sell them—here is his archived page about the Dymotec 6:

Per Peter (and my experience), this will power modern 6-volt lights, with or without a taillight (max of 3 watts of power draw).
<IMG_0325.jpeg>
<IMG_0326.jpeg>
<IMG_0327.jpeg>

The one I have is for mounting on the left side of the bike (it won’t work on the right side). The box has just the generator; you will need to supply the mounting hardware.

How about $45 shipped in the USA?

Let me know if you have any questions!

--Eric Norris
campyo...@me.com
Insta: @CampyOnlyGuy
YouTube: YouTube.com/CampyOnlyGuy 

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Peter White

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Corwin Zechar

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Dec 4, 2025, 7:00:34 PM (yesterday) Dec 4
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Hi Peter -

I'm really confused here. If Dymotech was "state of the art" 25 years ago... how is it the drag was about twice the drag of the SON dynamo hub, and the S6 and S12 hubs were somehow better?

Regards,

Corwin
Berkeley, California

Andrew Letton

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Dec 4, 2025, 7:24:37 PM (yesterday) Dec 4
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I'd venture to say that Peter meant "state of the art" for a bottle generator; obviously SON hubs existed then and were much better.
cheers,
Andrew

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