Don’t be a clown, tilt them down! – a bike light primer
- by David Halfpenny
- Published: 31 July 2014
Think about this: someone in charge of a thousand plus kilograms of metal is coming towards you at 50kph or faster. They will pass within a metre or two of you. The only thing between you and them is a stripe of paint on the road. Your light is shining in their eyes. It’s blinding them. Does that sound like a clever idea?
There have been a few threads on the Australian Cycling Forums recently about using bike lights in an anti-social manner. One thread was started by a motorist who was blinded by, and almost hit, a cyclist; the other thread was started by a fellow cyclist who was blinded on a bike path. These topics pop up regularly, so it makes sense to create a bike light primer. There is a lot to say about lights, and I suggest you do some research, but here are some things to keep in mind and consider when buying or using bike lights.
Do I Need Lights?
Yes. If you’re travelling in the dark or in low light conditions, you’re legally obliged to have them. You need a white light at the front and a red light at the back. They need to be visible from 200m away. That’s what the law says and you should consider that the absolute minimum requirement. A legal lighting setup however is not necessarily a useful lighting setup.
Day and Night?
You’ll notice that many motorbikes have their headlights switched on all of the time, day and night. Sometimes it’s the rider who does this, but often it’s a built in feature of the bike. Research suggests that it makes the motorbike more visible on the road and reduces accidents.
Following this theme, there are many cyclists who ride with flashing front and rear lights at all times. I haven’t seen any research on this for bicycles, but it certainly doesn’t hurt. Try it out and see if it makes a difference.
See or Be Seen?
Regardless of technological differences, all lights fall into one of two categories: lights to see with and lights that allow you to be seen.
Lights to see with are high powered lights with appropriate beam profiles that allow you to see your surroundings in the dark and while riding at speed. If you’re riding in the bush or somewhere with no street lights, you will need much higher powered lights. Experienced night riding mountain bikers will understand the need for these.
If you’re riding in suburbia where there are street lights and lots of other light pollution, you don’t need super high powered lights. No, you really don’t. If you are a road rider and you want to run with high powered mountain bike lights, use the light’s lower output settings. You don’t need really high powered lights in the city. No.
Lights to be seen with are lower powered lights and are designed to make you visible to others, rather than allow you to see with in the dark. You see these types of bike lights in supermarkets and department stores. They comply with the law, but not with reality. They do make excellent secondary lights and you should have one or two as back up. You shouldn’t rely solely on these to make your riding safe at night.
Rear lights are obviously only “be seen” lights. Some rear lights can be seen from the legally prescribed distance, but better rear lights can be SEEN from further away and from lots of different angles. Some rear lights can do even more.
Fixed or Flashing?
Both. Most lights have both modes and if you’re riding with your lights on during the day, flashing is a great mode to use. Flashing mode not only gives you longer battery life (since you’re not constantly draining the battery), it also makes your light more visible; flashing lights appear brighter. (It’s an effect of Bloch’s Law if you’re interested in Googling it). Flashing lights are not good to see by, however. Using a flashing light for navigation purposes is dangerous. For night time riding, your front light(s) should be fixed beam.
Rear lights are often used in flash mode regardless of the light conditions. I’ve read that having a fixed and a flashing light on the rear helps with (a) being noticed, and (b) helping depth perception of other road/trail users who are looking at your lights. The excellent thing about rear lights is that they can use very noticable flashing patterns and/or multiple synchronised lights, since you’re not using them to see with. They are the ultimate be seen lights.
It’s all about the lumens. Power is a measure of electrical power used by the light (i.e. voltage x current), while lumens is a measure of how much visible light is emitted. It’s actually an EU requirement that lights are labelled with lumens, though other measures can be used as well.
More lumens doesn’t mean better, since a single number doesn’t tell you important things like light beam profile, spread, spill, or even colour. You can have lights that have very wide and uniform illumination, you can have lights that have a very bright centre spot, and you can have lights that have a yellow or bluish tinge.
So how do you know if a light is fit for the purpose that you want? You really need to read reviews from experienced users, such as the ones featured here on BNA. Reading reviews or receiving recommendations from people who have used a particular light will save you a lot of money and frustration.
Front Light Mount Points
This is the most common location for front lights.
+ It’s a convenient location for turning lights on and off, and the lights can usually be easily removed and reattached to the mounts.
+ Good for most situations.
– The light is mounted high; for larger bikes this could be close to the eye level of a motorist or pedestrian. Typically the only adjustment up and down is by rotating the light around the handlebar.
– Bumping along the road can cause the light to angle up to motorist/pedestrian eye level.
This is a very common location for smaller, secondary “see me” lights. Not as good for primary lights.
+ The light points wherever you’re looking – so you can see in all the directions you look.
– The light points wherever you’re looking – so it may not be seen by people looking at you.
This was a typical location for mounting lights on older bikes and there were often dedicated attachment points on forks for lights.
+ Low to the ground, so as not to dazzle. Illuminates the surface you’re about to ride over.
– Hard to adjust while riding.
– Many bikes don’t have suitable mounting points.
– Many lights don’t have suitable mounts for forks or mudguards.
Rear Light Mount Points
This is the most common location for rear lights.
+ Usually provides the best location for maximum visibility near the center of mass of the rider.
+ Good for most situations.
– Can be obscured by seat bags.
The rear of the helmet is a very common location for smaller, secondary rear lights.
+ Good high mounting point for excellent visibility (in theory).
– The light moves with your head and so may not be seen by people looking at you.
If you’ve got extra furniture at the back of your bike, light that sucker up.
+ Rear most point of the bike for maximum visibility.
– Hard to adjust while riding.
– Many bikes or their attachments don’t have these mounting points.
– Many lights don’t have suitable mounts.
Ready, Aim, Fire
As I mentioned in my introduction, if you deliberately or accidentally shine your lights into someone’s eyes, you can temporarily blind them. You know what I’m talking about. The light receptors in your eyes become saturated and, even if the source of the light is gone, you can still be left with an after image that can blind you for several seconds. Several seconds while travelling at high speeds can be fatal.
Don’t be a clown, tilt them down. Aim your lights at the parts of the road or trail that you need to see and be conscious of other road/trail users. If you notice them reacting negatively to your lights, adjust them, either by tilting them down or turning them down to a softer setting. If that makes it hard to see your surroundings while you’re riding fast, simply slow down a bit. Riding is fun. Do what it takes to keep riding.
There is certainly a lot more that can be added to this primer, so if you have any rules or advice every rider should know, let me know in the comments below.