AT fender taillights in polished finish: temporarily sold out!

We’ve sold out of our first batch of polished fender taillights. We still have stock of taillights in brushed finish, as well as AT headlight mounts and TMAT stem switches. We are working on batch #2 of polished taillights and should have more available by this time next week. The polished AT fender taillight has proven popular!

If anyone has an interest in a one-off surface finish other than polished/brushed (color anodized, perhaps?), shoot me an email. It’s possible to do custom one-offs now and then, especially when in assembly mode.

Thanks for all the interest, and faith, in Velo Lumino components!


A letter from a customer

A customer asked me if I had a place to post reviews. I said I didn’t, so he wrote me a letter to post on the blog. Here it is:

I ordered a polished taillight from Velo Lumino for a customer’s Velo Orange Polyvalent 650b bike. Before ordering it, I received several prompt and informative emails from Anton about the light assuring me it would work with customer’s dyno hub and complement front light. The light arrived very well padded with well thought out instructions, while the light, lens and overall design has a well executed presentation to it. It compliments the style of my customer’s bike and personal taste. Wiring was easy. Light sits properly on the rear fender after a quick drilling of the hole to secure the light. Customer has only used it 3-4x on a 40 minute roll home and says he is very pleased with the light as it offers much brightness in a small package while ensuring clean aesthetics… Congratulations to Velo Lumino for a nice product! I would highly reccomend Velo Lumino products for their thoughtful, high quality and good designs and prompt courteous service.

Kind regards,


Port Townsend Cyclery

Thanks, Bob! That makes our day!

You’re invited to the Ball!

The New England Builders’ Ball, that is. We’ll be sharing a booth with our good friends at Sinewave Cycles. Come see both of us at booth #18, or just look for our logos. We’ll have all our components on exhibit for you to see and touch: the TMAT stem switch, AT fender taillight and the new AT fender headlight mount. Sinewave Cycles will have their excellent Revolution and Reactor dynamo-driven USB chargers. We hope to see you there!

The TMAT stem switch adaptor for 1-1/8″ steerers is available!

Velo Lumino is now stocking the adaptor necessary for installing the TMAT stem switch on bikes with 1-1/8″ steerer tubes. The switch was designed to work with 1″ steerers, with the idea that it could be made compatible with 1-1/8″ steerers via an adaptor if there was demand. Well the people have spoken, so we made a batch of these adaptors. The adaptor provides a perfect fit with 1-1/8″ steerers and stems, and adds only 1.25mm of stack height below the switch. With the adaptor, the switch preloads the headset and stem just like an ordinary stem cap, and the switch looks just as integrated as on a 1″ steerer. So for all of you who have been pining for the TMAT stem switch but weren’t able to take the plunge because of your 1-1/8″ steerer tube, you’re in luck! Available at The photos below show the switch with adaptor on a bike with a 1-1/8″ steerer.







Pro tip: how to create an elastic coiled wire for dynamo wiring

One tricky place for wiring is between the fork and the frame, regardless if you are running the wire internally or externally to the frame. Unless your bike has a carbon brush in the steerer à la René Herse, the wire has to pass externally from the fork crown or the fender to a hole in the downtube. What’s more, the wire has to have slack in it to allow the fork to turn without pulling the wire. I’ve seen all sorts of solutions to this, but none of them are perfect. The best approach I’ve seen is a wire that coils like an old fashioned telephone cord. Most of the Installations I’ve seen this way get it wrong. You can coil wire around a pencil or something similar, but it won’t keep its shape: one pull and it the coil straightens back out. That’s because when wire is made, the plastic coating is melted on and fused while the wire is held straight and taut, and then cooled rapidly. So even when the wire gets wound onto a spool for distribution, the plastic has “memory” and wants to straighten. Depending on the formulation of the plastic wire wrapping, it’s possible to “re-train” it keep the coil shape simply by heating it enough but not too much– or it will melt. Here’s what you’ll need:  wire, a narrow rod like a fender stay (you can even use one on your bike without removing it), and a heat gun (a hair dryer doesn’t get hot enough).

  • coil the wire tightly around a narrow rod, like a fender stay (you can even do this on the bike!). Pencils and pens are too thick (and pens might melt).
  • hold the ends in place or tape them in place so the coil doesn’t unravel when you let go.


  • use the heat gun to heat the wire evenly– test a small piece beforehand to make sure it doesn’t melt.
  • allow the wire to cool. Sometimes cooling it rapidly by running it under cold water for a few seconds helps the wire learn its new shape.

Voila! You’ve now got a coiled wire that will remember its shape even after repeated stretching. Note that not all wire can be “re-trained” this way, but the premium 22AWG wire that we sell works well for this trick!

Paint-matching the TMAT stem switch

The TMAT stem switch was designed to look great on a classic bike. Its knurled edge and polished cover complement bikes with silver alloy parts and polished details. But it can also look great on a modern build with black components. I’ve been running an early prototype of the TMAT stem switch on my daily rider, a Bike Friday Haul-a-Day. It’s a long-tail cargo bike with 20″ wheels and mostly black utilitarian components, so I painted the cover to match. For black, it’s easy since most any black paint will do. I used a matte black spray paint:



If you’re having a custom bike built or having your bike repainted, you can ask the painter to paint match the cover to the bike!

Our components are trusted by long-distance randonneurs

Our components accomplish simple tasks– closing or opening a circuit, or shining light. But they need to perform their tasks reliably.  They will work on any kind of bike whether a city bike or a bike designed for long distances, but it gives us particularly great satisfaction to know that some long-distance randonneurs are trusting our lighting components to keep them safe and seen through multi-day brevets and other endurance rides which take them through the dark of night. In these endurance events, riders can’t afford to be let down by failing components! Two of our earliest customers, both accomplished randonneurs, will be staying lit with the AT fender taillight through the long nights of the most famous randonnée ever, the 1200km Paris-Brest-Paris which starts in two days! We couldn’t be more proud and we wish the PBP riders a safe journey!

PBP bike with AT fender taillight
Photo courtesy of flickr user Vélocia

What testing goes into the components we design and build?

The Velo Lumino TMAT stem switch and AT fender taillight were developed not because we wanted to sell stuff, but out of a desire for components for our own bikes that don’t already exist. No one makes a switch like the TMAT stem switch. Some independent fabricators have built outwardly similar switches that mount in the same location, but these are mostly DIY products that involve assembling multiple widgets and using off-the-shelf switching components, and they compromise the field serviceability of the bike because of their specialized installation requirements. So Tom and I re-thought the concept of a stem switch from the ground up. Tom designed the mechanical aspects of the switch, while I designed the circuitry contained inside. One of the most important criteria for us was reliability. We wanted the switch to last a long time, and we wanted it to perform reliably in any environment.

On our first prototype, Tom tested whether the mechanism would withstand 10,000 continuous cycles of rotation by rigging it up to his lathe. The unit got really warm from testing, but the mechanism not only didn’t disintegrate, it also felt the same after 10,000 cycles as it did before starting the test. If you browse through an electronics supply catalog and look at switch specifications, most consumer switches are rated to less than 10,000 duty cycles.

We also wanted to test whether the switch would work in extreme operating environments. So we subjected the switch to freezing– deep freezing. We froze the switch in a calibrated laboratory deep freeze freezer, all the way down to -80C (-112F). Yes, minus one hundred and twelve degrees Fahrenheit! IMG_6134Okay, admittedly the switch did freeze up at that temp, and wouldn’t turn (the Phil Wood grease had hardened at that low temp). But honestly, there isn’t anywhere on earth that cold, and if there were, there would not likely be cyclists! So we tested it at a more moderate -13F, closer to Minnesota frigid. The switch worked fine, and didn’t feel any different than at normal temperature. Then we tried baking the switch. We heated it in a calibrated incubator to +80C, or +176F. That would be like baking the switch on the dashboard of a closed car. In the sun. In Death Valley, California. Again, the switch felt the same, and functioned the same, as at normal temperature, but I had to wear oven mitts to test it!

We designed the switch around magnetic reed switch technology because reed switches are impervious to environmental conditions. They are immune to moisture and corrosive agents. So we wanted to put this to the test. We submerged the switch in a tank of water, and asked if it could reliably switch a test light on and off. Repeatedly. For hours. It was unaffected by being in water. (We also designed the switch to have built-in drainage, so that if water enters the switch body– which we designed knowing it will happen, it can effectively drain out the bottom via the steerer tube and not cause potential long-term problems).

On-bike test rig for prototype #1. My winter commuter has a quill stem, so the switch was installed in a short piece of steerer tube and zip-tied to the stem!

Lastly, we asked whether the switch would withstand prolonged vibration, such as a bike would experience on many roads, especially when ridden on dirt and gravel roads– one of my favorite types of riding. So we subjected the switch to a shake test. We clamped it to a calibrated orbital shaker, and shook it at 900 RPM for three hours. In case you’re wondering, 900 RPM on this shaker is like riding really fast on a washboarded dirt road. The kind of shaking that rattles your bones and shakes parts on your bike loose. When was the last time you and your bike suffered like this for three hours straight? All the while, the switch was hooked up to a test light, and never wavered.

An early TMAT stem switch prototype. The switch that went through the “torture suite” of tests now serves daily duty on my summer commuter.

On top of controlled lab testing, the switch was also tested in situ on my daily commuter for over a month, during which time I made a point of turning the switch on and off at least a dozen times each ride. And it’s perhaps the on-bike testing that was among the most valuable, as that allowed us to fine-tune aspects of the switch’s design that only come under scrutiny while riding a bicycle. Like the feel of the rotary knob: early on, we thought we had the feel of the detents that define the Off and On states of the knob perfectly dialed in. Then one cold January day when it was -4F outside and I was wearing bulky lobster gloves, I couldn’t tell whether I was turning the knob or not without looking to see. This led us to dial in more tension in the ball bearing detent mechanism that provides tactile feedback to the user about what the knob is doing. We not only designed the switch to be reliable in extreme situations, we also designed it to “feel” right.

Oh, and that early prototype that went through all that testing? It’s now in regular use on one of my bikes, where I don’t even think about it: I expect it to continue to remain as durable and reliable as the production units.

The AT fender taillight went through similar stress testing before going into production, which is why we’re confident enough to stand behind it, and all Velo Lumino components, with a 3-year warranty. Any components that we develop will go through similar rigorous testing and will be held to the same high standards.