Transplant Surgery: LED into vintage headlamp

Initially I just used a Planet Bike Blaze dynamo powered light, which did not look period at all.

I recently swapped a new front wheel with a Sturmey Archer X-FDD 6 volt, 3 watt dynamo hub with cable actuated 70mm drum brake to make my 1936 Raleigh a bit more practical as a regular commuter bike.  The hub dramatically improved my braking and freed me from battery powered lights, but nobody makes a bright LED vintage looking light.  I had both a an old headlamp and an old Busch and Muller DLumotec Oval Plus with a power cable wires broken so close to the housing that they could not be repaired.  

This is what the housing, the lens, the heat sink, and the reflector from the DLumotec after I took them apart to get to the electronics.

I took both into Dr. Frankenstein’s workshop to do a little surgery.  The DLumotec is designed not to be serviced. It is not possible to get it apart without destroying the housing to some degree.  I didn’t care since all I wanted was the guts. I even decided not to use the heat sink, because I guessed that the vintage metal reflector would probably transfer heat better than the fancy heat sink in the original plastic housing.

Before I took the DLumnotec apart, I was not sure how I was going to fit the LED into the vintage light.  I must be living right though, because the LED fit snugly into the base of the old reflector.  All I had to do to secure it was fold over some metal tabs from the old reflector around the metal backing of the LED.  This not only held the LED in the reflector, but it also acted as a heat sink.  LED’s generate a lot of heat and they need a heat sink or they don’t last long. 

The LED fit nicely into the vintage reflector. All I had to do was ben over a few tabs to secure it.

I decided to simply leave the switch in the on position and stuff the guts inside the vintage rather than try to wire in a new external switch for the light.  I tend to leave my lights on even during the day as running lights to improve visibility.  Dynamo hubs have such low drag, that I don’t even notice the difference between when they are on or off.  It would not have been too much trouble to add the switch, but I must confess that I tend to pick the easy route when it comes to decisions like this.

These are the electronics from the Lumotec with the LED installed in the vintage reflector.


I wrapped the electronics with electrical tape to protect them and to keep it from rattling.The headlamp open and mounted on the Raleigh.

Bolt and mount

In order to mount the light to the Raleigh, I had to file a slot in the mounting bracket, which came off an old Japanese Skyway. The Raleigh mounting bolt had a key and the Skyway did not.   The headlamp is Japanese too, but rather than try to find an old English lamp, I removed the manufacturer badge and it looks period enough for me.

The LED fits really well in the old reflector.

The light is much brighter than any halogen light, but the reflector is not designed for the LED, so the beam pattern is not ideal. But since I use the light primarily to be seen riding in the city, a bright light with a less than perfect beam pattern is better than a dim halogen light with a better beam pattern.  That said, I may try to stick the original reflector inside the old housing to get a more useful light for riding unlighted trails. Stay tuned for the next chapter in saga of the ’36 Raleigh.

About Dave Schlabowske, Deputy Director

Dave was the first full-time staff member hired to open the Bike Fed's Milwaukee office 15 years ago. A former professional photographer and life-long Milwaukee resident, Dave likes wool, long rides, sour beer, and a good polar vortex once in a while.

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