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Advances in bicycle headlights

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by John Allen



It’s the time of year when bicycle commuters return home in darkness. Recreational riders might be returning at dusk. Lights are needed both for safety and to meet legal requirements.

While I’ve never had a problem finding adequate taillights, most bicycle headlights I’ve used over the years have been dim. I relied on streetlights to light my way in the city. Aimed level, my headlight would alert other road users to my presence. When touring, I’d use generator lights and aim my headlight at the road. With dark-adapted eyes, I could putter along without hitting too many potholes.

That was then, and this is now. Light-emitting diodes have produced not only a great improvement in brightness, efficiency and convenience, but also a proliferation in types of lights.

I’m not going to go into detail about novelty lights which make pretty patterns in the spokes, or bicycle gloves with flashing turn signals (though I do use reflective tape on my gloves—flashing by rotating a wrist back and forth) . Headlights have had most important advances, but these also raise concerns.

The USA has no standard for a bicycle-headlight beam pattern. Headlights are being promoted with lumen ratings—total light output, no matter where the light goes. Many bright bicycle headlights have a round beam pattern like a flashlight’s. If aimed at the road, the beam is unnecessarily bright up close, making it harder to see more distant objects. If aimed so brightness tapers off closer to the bicycle for even illumination, then the brightest part of the beam glares into the eyes of people ahead and washes out the view of the road in rain, snow or fog.

flashlight beam
Flashlight beam pattern, greatest brightness in the middle.

Certainly, for off-road riding, you’ll want to see the overhanging tree branch which could smack you in the head, but on roads and paths shared with other users, a shaped beam pattern like a car headlight’s avoids blinding people and puts more light on the riding surface. This beam pattern has a sharp, flat cutoff at the top; brightness tapers off below that. Most LED headlights with a shaped beam pattern are recognizable by their scoop-shaped internal mirror, curving down from the top rear to the bottom front, with the LED hidden up at the top rear.

German law requires a shaped beam pattern and 3-watt generator power, so Germany has led with generator-powered systems. Lights and generators are sold separately, and there are several brands. Bicycle tourists and randonneurs prefer generator systems. Prices range from $150 to over $300, though also, there’s the expense of building a hub generator into a wheel.

shaped beam
Shaped beam pattern: flat top, with sharp cutoff. Brightness tapers down
toward the bottom for even illumination closer to the bicycle.

Rechargeable battery-powered lights with a shaped beam pattern are available at prices from $93 to $250 from European manufacturers—but also from Dosun and S-sun of Taiwan, at lower prices. Some use replaceable AA batteries or an external battery, so it is possible to carry spares, but any of the battery lights will run for at least a couple of hours on their highest-power setting. The highest-power setting can be reserved for high-speed descents and rain, snow or fog.

I’m pleased to see local shops carrying more and more of these lighting products, and in enough variety to suit different budgets and needs.

Finally, let’s discuss headlight Installation. Mounting the light on the fork crown or a front rack puts it in the clear—though a battery-powered headlight may be supplied only with a handlebar fitting, and be obstructed by the brake levers, hands, a rain cape or handlebar bag. Minoura offers a bracket to hold a handlebar-mount headlight below the handlebar stem. Aiming the headlight is important, but easy: the flat top of the beam pattern should go a bit below the horizontal.

All in all, you pays your money and you takes your choice, as the saying goes—but there are more and better choices now than only a year or two ago. Be safe out there!

Peter White, in New Hampshire, has several pages of very helpful information about bicycle lights;
An extended discussion of bicycle headlight options is online at

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