See and Be Seen: A Guide to Bike Lights

Good bike lights are a urban cycling necessity. At night, in the evening, in fog or rain, or in the early morning, it's essential that other vehicles in traffic can see you. (Much of bike safety is about taking away the "but I didn't see him!" excuse--lighting up at night is an important part of that.) Many states even legally require cyclists to use lights between dusk and dawn.

Bike lights range from inexpensive battery-operated LED "blinkies" to more expensive rechargeable lights to several-hundred-dollar dynamo hub-powered systems. What is right for you will depend on your riding style and your budget.


These LED bike lights from Planet Bike are affordable and bright.

Battery-powered, affordable, durable, grab-and-go LED lights. These are generally affordable and lightweight, and they're designed to make you really obvious to other people on the road. They'll do for riding on the ocassional poorly-lit street or trail on your way home, but for long trips on dark roads, you'll be better off with something that's really designed to light up the road in front of you.

LED blinkies usually have two settings: steady and flash. The flash mode uses less battery and is extra noticeable at night, and most people use this mode most of the time--which is why they're called blinkies.

Most of them come with small plastic mounts that attach to handlebars or helmets or seatposts. Many tail lights have a clip on the back that attaches to the mount or can clip onto bags, belts, or pockets. The lights can be easily and almost instantly removed from their mounts and tossed into a bag or pocket when you park your bike, and then reattached just as quickly next time you're riding in the dark. Australian bike accessories company Knog makes popular lights that don't require a mount of any sort--their casing is made of a stretchy silicon material that wraps around your handlebar or any other round part of your bike and hooks onto itself. Their small size makes them great back-up lights in case your batteries (or a friend's) die.

The Knog Beetle is just about as small and simple as it gets. Planet Bike's Blaze headlight and Superflash tail light are lauded as "obnoxiously bright" and they run on two AA batteries each, so replacements are easy to find and interchangeable.


An ultra-bright rechargeable headlight from Light & Motion.

Rechargeable lighting systems are usually more expensive and more powerful than blinkies. These are the lights to get if you really need to light up the path in front of you. Though they sometimes take AA batteries or another standard size, they burn through batteries much faster than blinkies, making rechargeables much more economical (not to mention environmentally friendly). Rechargeable systems usually come with both batteries and chargers.

The battery pack is generally separate from the light itself to reduce bulk. The light itself is either a halogen bulb, an HID (high-intensity discharge) lamp, or one or more LEDs. Historically, halogen lights have been considered brighter and more effective than LEDs, but LED technology has greatly improved in recent years.

For example, the DiNotte 140L Tail Light is powered by an LED that emits a whopping three watts and is well-known as the brightest tail light that money can buy--even Planet Bike's Superflash is hardly a flicker next to this thing. DiNotte's headlights, including the 200L, which comes in a long-lasting Lithion-Ion version and a standard AA version, are similarly bright.

Even Light & Motion, maker of highly-esteemed professional bike lights for 24-hour endurance racers and the like, have shifted from using halogens or HID lamps to using LEDs for their lights. LEDs are more durable and last much longer (probably longer than your bike!), and are capable of brightness that was unimaginable just a few years ago. Check out Light & Motion's top-of-the-line Seca 700 Ultra Light.


Rechargeable or not, batteries are a hassle. Bicycle generators (dynamos) produce their own electricity, which can be used to power lights, through the rotation of your wheel. They probably won't work if you want the lightest bike possible, or if you race on the weekends, but for the average city biker, their convenience is unbeatable. Dynamos are ubiquitous in European cities where utility biking is common; in fact, in Germany, every bike over a certain weight must legally be equipped with a dynamo system. There are a few types of dynamos available.

A trusty bottle dynamo hooked up to a headlight.

Bottle dynamos are also known as sidewall dynamos. They consist of a bottle-shaped unit attached to a bike's fork, with a roller at the top that is placed against the tire's sidewall, so that when the wheel rotates, the roller spins, generating electricity.

Bottle dynamos add drag to your wheel, for sure, but high-quality ones can be aligned such that pedaling won't feel too much like a struggle. The dynamos can also be disengaged completely when you don't need your lights on. They've been around forever and are fairly "tried and true"... but be aware that older bottle dynamos, and cheaper new ones, may blow out your lights when used at higher speeds! This is yet another problem solved by new LED technology (and voltage limiters built into the dynamos).

Special lights are made to work with these (and other) dynamos--Busch & Müller's Lumotec line is popular. Lots of detailed information is available on the internet, for example at Peter White Cycles here.

Bottom bracket dynamos seem to be pretty uncommon these days, but they work similarly to bottle dynamos. They attach behind your bike's bottom bracket below the chainstays and have a roller that's placed against the tire's tread.

Magnet lights are powered by magnets attached to a wheel's spokes. The light itself is attached to the hub, and when the wheel rotates and the magnets pass by the light, electric current is produced. In the simplest of these lights, the light flashes every time the magnets pass by. They are quieter and produce less excess friction compared to bottle dynamos. Reelight is one manufacturer of these lights.

Hub dynamos are perhaps the ultimate solutions: they allow you to fully integrate lighting with your bike. With no added elements to strap to your bike, they are aesthetically elegant. The newest dynamo hubs from companies like Shimano and Schmidt are reportedly so efficient that any tiny amount of drag they add to your bike is pretty much unnoticeable, unless maybe you're a time trialist counting tenths of a second. Hub dynamos are built right into your front wheel. Your lights are connected via wires at the axle.

Some dynamo systems even have a built-in automatic switch that turns your light on when the sky starts to dim.

One thing to be aware of with all generator systems, no matter what kind of dynamo they're powered by, is whether or not they have a "standlight." Because dynamo-powered lights are powered directly and instantly by the power generated by the rotation of the wheel, some older lights and cheaper newer lights turn off as soon as the wheel stops rotating. In city traffic, this is very dangerous! It's important for drivers to see you while you're waiting at an intersection or waiting to make a turn. So, lots of lights have integrated standlights, which means they have a capicitor or small battery that stores a little bit of power to keep your lights lit for a few minutes after you've stopped moving.


Bike lights have been essential bicycle equipment for just about as long as bicycles have been ridden in cities!

All of the above will have you pretty well lit from ahead and behind--but what about the side? Some light from your headlight and tail light will spill out to the sides as well, but many cyclists like extra lights for extra visibility or just a bit of bright fun. Last week, we reviewed the Monkeylectric Monkey Light and covered some other spoke light options. Here's some more possibilities:

This light-up ankle strap not only flashes brightly, it'll keep your pant cuff from getting caught in your chain. Or you can use it as an arm band, on or off your bike.

The Down-Low Glow is a colored tube of light, powered by a rechargeable battery, that you strap to your downtube. It casts a pool of light below the bike that's visible from pretty much any direction.

Pedalite pedal lights generate their own power when you pedal to light up three LEDs on the outside of the pedals. They are as easy to install as any other pedals and include a standlight feature--that is, the lights won't go off immediately when you stop pedaling at an intersection or on a downhill.

Stay safe, stay seen, and have fun!

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