Guidance for cyclists on bike lights

You might wonder what there is to discuss about bike lights. But in my several years as an urban commuter cyclist, and with my fascination for toys such as bike lights, I’ve made some observations which might prove useful to other cyclists.

What you need

Before you go out and buy a light, decide what your needs are. Choose a bike light to suit your needs (and budget, of course). If your daily needs cover two or more of these categories, you should consider buying either a light which ticks all of the right boxes, or two lights.

Use	What you need
In traffic on lit roads	Flashing LED lights to be seen by drivers Consider head-mounted ones to be seen above cars.
In traffic on unlit roads	Flashing LED lights to be seen by drivers Constant lights to cast light onto the road Consider head-mounted ones to be seen above cars.
On a lit, off-road cycle path	Constant lights to be seen by other cyclists
On an unlit, off-road cycle path	Bright constant lights so you can see where you’re going! You might be better off with halogen bulbs rather than LEDs here.

How to mount your lights

When you are riding in traffic and your lights are in flashing mode, I would recommend angling your lights directly forward. Most LED lights are not bright enough to dazzle other drivers, but pointing them forwards will make them appear much brighter, and will cause them to shine into the wingmirrors of cars in front of you.

If in doubt whether your lights are too bright, or inconsiderately aimed, sit in a car and get a friend to ride your bike at you 🙂

When riding with very bright lights, it’s plain rude to point them into driver’s eyes. Dip them like every other vehicle.

When riding on an unlit path, don’t use too much light because it dazzles other cyclists. Keep your lights aimed low. Flashing lights aren’t required here to attract attention, and the flashing can make it hard for oncoming cyclists to see.

Branded vs generic

As a student, I was strapped for cash and I would always buy cheap, generic bike lights from eBay. Now I have a job, I always buy Cat Eye.

In my experience, the cheap lights are usually similar in brightness but the beam pattern is never as good as a branded light. Most importantly, the cheap lights have very poor quality brackets which usually snap off long before the light breaks. One such light whose bracket broke has now been turned into a makeshift photography light, which I gave to my brother. I’m so generous!

Nowadays I almost always buy Cat Eye. They are the Coca Cola of the bike accessories world, and I’ve always found them to be consistently high quality in terms of the brackets and the brightness, beam pattern and battery life are excellent. They’re not the cheapest, but I reckon you’ll be pleased if you buy them.

Carrying spares

I think it is crucially important to carry either multiple lights or multiple sets of batteries with you while commuting. Especially with LEDs, it’s not always obvious when the batteries are running out so it’s easy to be caught short. If your lights run from AA/AAA batteries then it’s no problem to keep a spare set in the bottom of your bag all the time.

If you’re lucky enough to own a set of lights with a rechargeable battery pack, it’s not always practical or possible to carry a spare set with you. In this case you’d be wise to keep a spare LED light with you. Doesn’t matter if it’s a cheap one 🙂

Multiple lights

As well as keep a “spare” set with you, you might want to mount two or more lights on your handlebars.

I find that having two lights on the handlebars, both flashing, is a great way to attract attention. They never quite flash in perfect time and this effect is rather eye-catching.

It also means you can put out twice as much light when running in constant mode, which is great news if your commute takes you on unlit roads or paths.

I have 5 headlights on my bike. I have a pair of RSP Asteri 2 LED headlights which I use in flashing mode in the city and dim constant mode on the Bristol-Bath bike path. I have an extremely bright pair of Cat Eye ABS-35 halogens to be used on the unlit sections of the path when there are no oncoming cyclists. They have a thumb switch to turn them off quickly if anyone comes into view. And I also have a head-mounted flasher, a Cat Eye HL-EL400.

Head-mounted lights

Head-mounted bike lights are a controversial topic among cyclists and motorists.

I use a helmet-mounted front and rear light because they can be seen over the tops of cars in heavy traffic. It used to make me nervous that if I was currently being overtaken, the car behind the overtaking car might not be able to see my rear lights mounted in the usual place, below the saddle.

I also think it’s very versatile because you can choose to direct light wherever you turn your head. Part of my journey takes me along a stretch of road that has two lanes. Drivers frequently change lanes without looking sideways, where I often am. If I have a head-mounted flashing light, I can look into the car window, directly at the driver, and then they usually notice my presence.

However, one of my colleagues who drives (and also cycles) says he dislikes head-mounted bike lights because it is impossible to see a cyclist’s eyes and therefore the driver can’t always tell if the cyclist has seen the car.