The New Compass Taillight


When building my René Herse randonneur bike, I was unable to find a taillight that combined the functions I needed along with a classic appearance. I ended up making my own taillight. Now this light is available from Compass Bicycles Ltd.

I wanted a generator-powered taillight that matched the appearance and style of a classic, hand-built custom bicycle. The plastic tailights from Europe did not meet that criteria and were not appealing. I also wanted the light to incorporate a reflector, both as a fail-safe and to comply with legal requirements and the rules of randonneuring events.

I wanted reliable internals, and not custom-made electronics. The light had to survive many years of spirited riding on rough roads. It also had to be lightweight.


Bicycle Quarterly contributor Hahn Rossman suggested using the reflector as the lens of the taillight, which creates a nice, diffuse light. This reduces the glare for riders following you closely, yet it is no less visible from a distance. (The reflector doesn’t reflect the other way, so it doesn’t absorb more light than a normal red taillight lens.)

The Compass taillight has a machined aluminum housing. The reflector is EN-approved. (We tested a number of reflectors and used the one that reflected best, while also being thin enough to work as a taillight lens.)


Inside the aluminum housing are the electronics and LED of the Busch & Müller Seculite Plus taillight, which include a standlight. The circuit board mounts to a custom-made stainless steel plate, so it is securely attached. The stainless plate also serves as an attachment for the grounding wire.


The light comes with a custom-machined, two-piece braze-on. Your framebuilder can attach this behind the seat tube of your bike, René Herse-style. The screw-in piece provides a conduit into the seat tube, so the wire doesn’t snag on the sharp edge. It also provides a stop for a seatpost that otherwise might be inserted too deep and cut the wire.

The braze-on is pre-mitered for the seat tube, but your builder also can braze it to the end of a tube, if you want to use the light on a rack. You could also mount it underneath the chainstay, Alex Singer-style.


The light comes with ample wire to reach the headlight. The wire itself is a special automotive wire. The insulation is made of a cross-linked polymer with extra-high abrasion resistance.

The Compass taillight carries a 2-year warranty. It is made in the USA, and available now. More information about the Compass taillight is here.

About Jan Heine, Editor, Bicycle Quarterly

Spirited rides that zig-zag across mountain ranges. Bicycle Quarterly magazine and its sister company, Compass Cycles, that turns our research into high-performance components for real-world riders.
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32 Responses to The New Compass Taillight

  1. David Pearce says:

    Wow! That’s a tour de force! Congratulations to Compass Bicycles!

  2. Sean says:

    This looks beautiful!

    Could you please list the lights dimensions?

    Would it be viable to attach it to the rear fender?

    Thank you!

  3. Nick says:

    Fantastic news! I have been waiting for something like this for ages. Boulder Bicycles makes a battery-powered light that mounts in the same location. I have recently ordered a custom frame (to be delivered this week!) with Boulder’s M6 braze-on attached. It would be fantastic if this light will fit that mount so I can install a wired taillight in place of the battery-powered one! I am in luck or am I stuck with battery?

  4. Champs says:

    It’s great that you’ve added this feature. The lack of a taillight reflector lens is my only quibble with the Supernova E3 system I use.

    But if the light is a letdown, so are most fenders, too. It’s hard to think of a reason for any full coverage rear fender not to have an integrated reflector, or at the very least a bracket to install one. This is a basic feature of 40 year old bikes.

  5. cory.b says:

    Wow great work! I was wondering when the next Compass masterpiece would arrive. What is the diameter of the lense on this tail light? Have you thought about making a similar version in more of a fender mount type? Great design!

    • The diameter of the light is 37 mm. The lens diameter is about 34 mm.

      We’ve thought about a fender-mount version, but it would have to be a different design. If you wanted to mount this light on a fender, you’d need an indent in the housing, like many old French reflectors have. However, that would not leave room for the capacitor for the standlight inside.

      Simply lengthening the light wouldn’t be aesthetically pleasing. I wouldn’t want the light to look like a cancerous protuberance that grows out of the fender!

  6. cory.b says:

    Also, Jan is this your Rene Herse in the photos with box lining on chrome ?

  7. Ryan says:

    Please consider a fender mounted version of this. I would pick one up in a heartbeat.

  8. Max Sievers says:

    Why don’t you include the stop light function by B&M? See:

  9. Nate says:

    Thanks for the great addition to the tail light market Jan! I purchased a boulder randonneur just before the design of the tail light mount. I have the very awkward looking Y bracket protruding from just under my seat. I am wondering if there’s a way to make use of this bracket with this light. If not, I wonder how expensive it would be to have a frame builder detach the Y bracket and then attach the mounting mechanism for this new light in the location you mention above… Thanks again!

    • TobinH says:

      I think any local machinist could make you up a subtle little bracket that would work for this. You may have to ply him with beer or something, and sometimes finding a guy who is willing to take on little parts like this is a challenge. Sometimes bike shop employees and frame builders will know of a guy.

    • Conrad says:

      Contact haulin Colin if you’re in Seattle. I had them braze some eyelets onto my commuter for mounting metal fenders. An M6 attachment for the light would probably be similarly easy.

      • The Compass taillight comes with a braze-on. Adding that to a frame would be very easy, and if you have a good builder, they’d burn only about 1″ of paint either side, which you could touch up.

        Many riders around here added cantis to old road frames to ride in cyclocross… For the taillight, you could use silver brazing, which uses even less heat.

  10. Thank you for making the effort to bing products like this to market. Availability is the first step. As awareness grows, so too will demand.

    A few years back I remember people talking about the Renaissance of cycling that was upon us. Things are just getting started, and the application of craft, quality and function are creeping towards volumes that make the business more viable.

    Thank you for this and all your other products that help to widen the pond of practical cycling

  11. WLamb says:

    Brilliant! I recently installed a m6-tapped pannier boss on my seat tube a la Herse and was wondering how to convert an old miller light… no need! Take my money now!!

  12. kidalv says:

    Nice light, but shouldn’t it be called “Tail Light” rather than the odd hybrid name “tailight?”

    Grammer police on the prowl…

  13. edubya says:

    Thanks for making such useful and elegant products. On this tail light and the Edelux lights, did you consider having the pc board potted into the enclosure to increase durability?

    • We did consider it, but decided to leave well enough alone. Over years of riding in all conditions, we’ve had zero failures of the B&M Seculites, which is why we picked the electronics from that light. Our light is sealed much better than those. Coating the electronics in epoxy would reduce the heat transfer, and that might lead to problems.

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