LED Light Conversion continued

Back at the end of November in 2017, I wrote a post on my conversion of a Soubitez headlight/taillight combination from halogen incandescent bulbs to modern LEDs. LEDs have revolutionized bicycle lighting and I was looking for some of that improvement for the lighting system on my Bertin C 37 randonneuse conversion. Many modern lights built for LEDs have superior optical properties and light dispersion compared to the old incandescent or halogen setups from the 1970s or 1980s. See the Peter White article here for photographs of beam patterns. Unfortunately, many of these lights are

Credit: Peter White Cycles

functionally excellent but ugly in appearance. That was part of the initial motivation for converting my old Soubitez. Another concern was that the older setups came as a single wired format. Current flows from the bottle generator, through a single wire to the headlight and through another single wire to the tail light and is grounded through the steel frame to complete the circuit. The newer headlights all look wired for a current and a ground wire which, I assumed meant re-plumbing the the bike’s internal wiring routing and lashing up a return wire in the rear fender. This is not viable due to the small diameter of the frame drillings for the current carrying wire and the small diameter of the fender edge roll where the tail light wire is tucked to avoid the tire’s tread. Ultimately, I was looking for a plug and play solution in which I simply replaced the original halogen bulbs with much higher performing LED  equivalents.

Thankfully, that was easier than anticipated and the headlight bulb was replaced with a 120 lumens 1W white LED  from Bike Co. in the UK. The rear worked out just as well as Compass Bicycles in the U.S. sells a red .35W LED with a built-in standlight. As seen in the previous article, installation was straight forward and the results were promising when tested indoors. However, on the road, the results were disappointing. At the time, I wrote, “The light intensity is sufficient around town and gives sufficient light to the front if one travels slowly. It would be readily possible to out ride the light.” While the rear with the stand light was excellent, the front under performed for my expectations. When I first test rode the lights, I re-aimed the headlight several times to get a passable pattern of light but there was no real throw to the light and it fell away quickly at the edges leaving a real possibility of out riding the light at little more than walking pace or in a turn.

The poor performance of the headlight conversion continued to bother me after last year’s article and I continued to tinker with the headlight alignment over the summer and fall of 2018. On one occasion, I took a different route for the headlight test which took me onto a multiuse path with trees at the sides. The trees were well in leaf and as I rode by I could clearly make out details on the upper trunks and lower leaf canopy illuminated by my headlight beam. Obviously, the lens design on the OEM Soubitez headlight was deficient and the bright white light from my LED was going to a lot of places other than the road. Equally obvious, I needed to change the headlight. (The photo to the left shows the Soubitez with the original halogen bulb.) The light was mounted on a custom cro-mo chromed bracket made by Mariposa/Bicycle Specialties of Toronto. Any replacement would need to conform to the tab arrangement as shown in the photo to the right. So, the headlight search was on and a great deal of time was spent going through sales sites on-line looking for a period correct but effective light. Union, Soubitez and Sanyo all had possibilities but very little was available in the way of tests or anecdotal reports of the ones available since they pre-dated or barely overlapped the existence of the Internet. I was complaining about this to my brother who is a professional bike mechanic and he suggested I use his discarded stock of headlights from when he used to commute by bicycle. I agreed and he presented me with a shoe box full of headlights which included a Sanyo from a bottom bracket generator set, a couple of Union headlights and a couple of Soubitezs, one of which had been soldered up to a battery pack. Having salvaged three potential headlights, I sat down and cleaned all the bodies with citrus based solvent and then polished the bodies with Simichrome polish. I cleaned the three lens with Simichrome as well and the fine abrasive removed fine surface scratches and any road dirt or discolouration.

Given that Sanyo/Panasonic is a renowned maker of electrical goods, I determined to try the Sanyo first. I removed the 1W LED from the original Soubitez lamp and screwed it into the E10 dimension socket in the Sanyo after wiring the bulb base to the power wire on the Bertin frameset. I reassembled the Sanyo, screwed down the attachment screw, attached the light to the Mariposa bracket and roughly angled the headlight. I tested it indoors and the light seemed significantly brighter than the original Soubitez but seemed to have shadows in the beam pattern. I took the bike outdoors and rode it on the same multiuse path that revealed the original light beam pattern problem. The result was improved but there was an arch of shadow in the center of the beam and I still got to see way too much of the leaves of the nearby trees. So, no to Sanyo.

I was reluctant to try another Soubitez so I determined to trial fit the Union headlight as my next example. In conversation with my brother, it turns out that this might not have been the best course of action. He informed me that his experience with the Union using a 6V, 2.4W halogen bulb was that the headlight beam was divided into alternating light and shadow bars from one side of the street to the other. This had the disadvantage that road hazards like pot holes and pavement cracks “hid” in the shadow bands and created potentially dangerous problems for the rider. As can be seen in the accompanying photo, the strong vertical fluting probably contributed to that effect. So scratch that idea and back to doing the Soubitez next.

The Soubitez was similar in its superficial appearance. It had a similar, large clear lens and a black plastic bulb holder located at the back of the chromed reflector. The bulb mount had a twist and pull release system of lugs and notches to hold it in place and a molded socket to accommodate the bulb and the connecting wire. The 1 W LED simply screwed into place in the plastic socket and held the connecting wire tightly in compression. The Soubitez had a plastic mounting bracket with a copper insert unlike the original which mounted with a serrated steel tab. To be sure of a ground contact, I added a steel washer to each side of the plastic body bracket and the used an M5 screw to mount it to the Mariposa light bracket. The chromed  plastic lens and reflector unit then just twisted into place.

If the Union and the test Soubitez are compared, the Union has an obviously tighter sequence of flutes which may contribute to its banded beam pattern. An indoor test of the Soubitez indicated a brighter beam distribution of light. The subsequent outdoor test revealed a much better light distribution horizontally than the Sanyo, with better forward throw of the beam. The Mariposa bracket is bent slightly off-center which has to be corrected to center the beam. Riding the multiuse path revealed very little of the tree trunks or the leaves of the nearby trees, which has to be a great improvement all by itself. However, it must still be said that the headlight is  not up to riding at normal road speeds and remains unsuitable for downhills as the headlight beam can easily be out ridden. As well, the beam does not throw significant amounts of light sideways making cornering a matter of trust rather than observation. An unexpected benefit of the headlight change is that my handlebar bag no longer press onto the top of the light housing. The rear light LED remains unaffected by the changes up front and continues to offer  a bright red stand light feature visible in the dark as well as in well-lit suburban streets.

Conclusion: The changed front reflector is a considerable improvement in beam shape but the 140 Lumen output of the LED output may simply be too low for serious use. The up side is that things are better and still look period correct.


2 comments on “LED Light Conversion continued

  1. It certainly does. Those old French randonneuse bikes with the big D-cell flashlights attached to front rack had them there for a reason. I think a 500 Lumens LED light on the handlebars would be the solution or finding a 2 or 3 Watt LED for the Soubitez.

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