Your essential guide to what to look for when buying bike lights
It’s important to have quality bike lights fitted if you intend on cycling after dark. It’s a legal requirement to have a white light at the front and a red and the rear, and it’s dangerous to ride without them.
Most cyclists will regularly ride after dark in the autumn and winter months, making bike lights an essential piece of kit – but it’s also considered a sensible idea to use a beam in the day time too, to aid visibility.
Bright sunshine can be cited by motorists as a reason for not spotting a more vulnerable road user, a factor that can be negated by a set of bike lights switched on during the day to show where the rider is against the bright backdrop.
We’ve got more on everything you need to know when choosing a bike light below, but first here are some of our recommendations.
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Our pick of the best front bike lights
Front lights are classified as ‘seeing’ lights or ‘be seen’ lights.
Be seen lights mark you out on the road and are designed for use on lit roads. In this case, 100 lumens is a good starting point – but 300+ will let you see more of the road ahead.
Seeing lights highlight the road in front of you, and are designed for cyclists who want to ride unlit roads. Brightness of bike lights is measured in lumens, and you’ll need anything from 700 lumens, though 1000+ lets you ride closer to your summer speed as such a beam gives you more foresight.
‘Be seen’ blinker: Knog Light Pop II Front light – £19.99
This 60 lumen light offers just enough brightness to ensure you’re marked out on the road, and committed commuters might use it as a ‘back up’. The design keeps it simple with AA batteries and it offers 180 degree side visibility.
‘Be seen’ from further away: Exposure Switch front light – £78.70
Read more: Exposure Switch front light review
The Exposure Switch is the brand’s dedicated commuter light providing all the illumination you need to see and be seen while in an urban environment. It puts out an impressive 375 lumens though so you’ll be well marked out, but you can’t use it to see the road ahead on unlit lanes.
‘Seeing light’ for slower rides: Cateye Volt 800 front light – £99.99
Read more: Cateye Volt 800 front light review
At 800 lumens, this is just enough to commute on unlit roads and see where you’re going. It’s not so bright that it’ll show up the road just like a car headlight would, though, so you’ll need to adjust your speed accordingly. There’s six different modes and the battery will last between 2 to 80 hours depending which you run it on, taking 5 to 9 hours to fully charge.
‘Seeing light’ for moderate rides: Gemini Xera LED 950 – £99.99
The latest offering from Gemini after their Xera 850 release a few years back. The light follows the fundamental design of looking like a torch making it just as useful off the bike as well as on it. This puts out 950 lumens, which is enough to see well ahead of you on the road, allowing you to maintain a moderate pace through the lanes.
Also available from Amazon
‘Seeing light’ for fast rides: Exposure Toro MK9 front bike light – £294.95
Read more: Exposure Toro MK8 review
Designed with cross country mountain biking at front of mind, this light puts out a whopping 3300 lumens. Running it at full power might not make you popular on a changing, but of course you can use a lower mode and tacking the country lanes alone you’ll have excellent visibility. Just make sure you lower the mode for oncoming vehicles.
The beam is tight and focused – whilst Exposure’s more road going offerings (like the Joystick) will spread it out more. The run time is two hours and this one weighs in at only 236g.
Our pick of the best rear bike lights
Rear lights are a little simpler to classify – they need to mark you out from behind, ideally with a battery life you can rely on and and easy charging method. Here’s four we recommend…
Lezyne Laser Drive rear light – £57.99
Read more: Lezyne Laser Drive rear light review
At over £50, this is quite a pricey option – but it’s got a unique party trick. The 250 lumen rear bike light also incorporates laser beams which can be displayed wither side of the cyclist. This is designed to reduce the number of close passes cyclists experience, and cut down on SMIDSY moments. The mount is compatible with both round and aero seat posts, too.
Knog Blinder R70 rear bike light – £48.99
Read more: Knog Blinder R70 review
There’s nothing complicated about this Knog rear light, but it ticks all the boxes we look for when testing rear lights. It’s nice and bright, has multiple modes, a good battery life, is USB rechargeable, and will even fit the aero seatposts of the most aero of aero test bikes. Absolutely faultless.
Exposure TraceR rear bike light – £49.95
Read more: Exposure TraceR review
At £49.95 there are certainly cheaper rear lights on the market, but there aren’t too many better. Despite its dimunitive size the TraceR can still pump out 75 lumens, which is more than enough for a rear light, and the tool-free mount is ingenious.
Cycliq Fly6 rear camera bike light – £99.99
Read more: Cycliq Fly6 review
Finally something a little bit different, not only is the Cycliq Fly6 a 30 lumen rear light, but it is also a camera capable of shooting HD footage of what’s going on behind you. A useful feature is that if the built-in accelerometer detects that you’ve been in an accident it will automatically keep the footage, providing you with evidence to give to the authorities.
Also available at Amazon
Front bike lights: what do you need to consider?
We’ll look at specialist lighting options in a moment, but for now, let’s assume you’re a road rider or commuter who wants to see and been seen when the sun sets. What do you need to consider when buying your lights?
Most modern cycle lights use LEDs rather than old-school bulbs, and such has been the advancement of technology, these can be blindingly bright.
Of course light power is an important part of your buying criteria, but don’t let that be the be-all and end-all. Beam shape and the effect of the light lens can make a huge difference — we’ve seen lights of supposedly lesser power trump rivals when it comes to real-world performance.
All these factors are of most importance if you’ll be using your front lamp to actually light your way. But bike lights perform another function: to warn other road users of your presence.
If you’ll be riding on lit roads, you may find the need for an ultra-bright constant beam is unnecessary and a flash function at the front is perfectly adequate.
Bike lights and the law
New bikes are sold with reflectors and many people dress in high visibility clothing, which are good additions but in no way make up for a bike with no lights. Bicycle mounted illumination is essential for safety and to keep you on the right side of the law. A decent set of bike lights can be the difference between riding home safely or not getting there at all.
The law regarding bike lights is governed by the Road Vehicles Lighting Regulations, first published in 1989 but amended six times since, which says that as well as your pedal reflectors and rear reflectors (the side and front reflectors aren’t actually a legal necessity) night-riders will also need lights front and back.
The lights have to be mounted on the bike centrally or to the offside, positioned up to 1.5m from the ground, and conform to British Safety or EC standards.
Both front or rear lights can be flashers, but if so they must emit at least four candela. “But bike lights tend to be rated in lumens or Watts, what’s a candela?,” we hear you cry.
It’s not a particularly easy subject to explain, and they’re not directly convertible units. But simply put: as long as you buy decent quality bike lights, fit them properly, and remember to switch them on, the law shouldn’t be a problem.
Lumens and power
Lumens are used by the bike industry to measure the power of a light: a lumen is a unit of visible light. Since modern LEDs require far less energy, expressing their power in watts – which tells you how much energy they consume rather than how much light they produce – is redundant. For comparison’s sake, a 100W incandescent bulb emits 1600 lumens.
The more you pay, the more lumens you get, but lumens burn up charge, meaning that if you want to run a high-lumen light for a long period of time it will need a big battery.
For road riding on unlit country lanes, you need a ‘seeing’ light. This needs to be at least 700 lumens, though to ride fast like you would in the summer then 1000+ lumens is a safer bet as you’ll have longer to anticipate obstacles like pot holes.
To be seen when riding on lit roads, 100 lumens is a good benchmark, but 300+ will show you a little more of what’s going on at ground level ahead of you. At the rear, anything from 20 to 100 lumens is plenty.
Battery life and charging
For your rear light, the flash function is ideal. But if you’re a cycle commuter, with both front and rear lights also consider how effective the lamp is in terms of side lighting, as this will make you more visible from more angles and help avoid the “sorry mate, I didn’t see you” excuse from a turning or emerging vehicle.
It’s still generally a case of the brighter the better, but you also need to consider other qualities that will make your life easier. Look to see how many flash settings the light has; what the run times will be on a single charge or one set of batteries; and see if it has a rechargeable power source.
In this case, check if it needs its own special charger or if it can be recharged via USB, which aids convenience immensely. Some lights even have a helpful gauge showing how much power they have left.
Bike light mounts
The last consideration is mounting. Smaller bike lights may be simply mounted using a rubber or silicon strap, whereas big lamps — especially front lights — may require a proper bracket. Truly powerful front lights may even feature an external battery pack that will also need to be accommodated on the bike.
In any case, if you’re planning to leave your bike parked up in public for any length of time, make sure your lamps can be easily removed.
Rear bike lights: what do you need to consider?
Thought the amount of power you’ll need for your front light will vary depending upon where you’re riding, no cyclist should be without an adequate rear bike light. Rear bike lights will usually omit around 30 lumens or more, and generally have several modes: steady light, flashing, or a combination between the two. All options are safe and legal, but a flashing mode will usually help to save battery life.
There’s particular argument for using a rear bike light even in the day time, because it will help drivers pick you out from behind. It’s also a sensible idea to double up on rear lights. Though it’s unlikely, you won’t be quite so aware if your rear bike light fails as you would be in the case of a front beam, so having a back-up fitted can provide extra security and peace of mind.
Back-up bike lights, helmet mounted bike lights and extra brightness
The typical cycle commuter on urban streets will only need a relatively simple set of front and rear lights. There’s still every reason to buy the best you can afford, and even double up with an extra set of cheap emergency-only flashers front and back. But if you’ll be riding off road or on unlit country lanes, you really do need to go for the bigger, more powerful lamps with wider beams.
To augment their bike-mounted lamps, many riders also opt for helmet-mounted lights. These can be very effective and have the added benefit of directing the light wherever you are looking. However, these should be in addition to those on the bike, and not your only source of illumination.
Another sensible option is the dynamo light. This uses a compatible hub or wheel-rubbing bottle dynamo to convert your forward motion into electricity which then powers the light — so no need for batteries. Bottle dynamos can be disengaged in daylight hours so they don’t drag unnecessarily, and at night-time it means you’ll never need to worry about run times or recharging again.
Super safe accessories
Night riding isn’t just about illumination. In recent years a whole industry of associated safety accessories has come about.
For example, the Blaze laser light combines a high-powered rechargeable front lamp with a warning image of a cyclist projected by a built-in laser onto the road ahead of you. Similarly, the Xfire Bikelane looks just like a typical LED rear light, but it uses lasers to project virtual bike lane markings either side of you.
There are some smart options out there designed to improve your safety. For example, See.Sense lights are clever front and rear lamps that use inbuilt sensor technology to flash brighter and faster when cyclists are in potentially dangerous scenarios.
There are more innovative products appearing all the time, so do enjoy exploring the world of cycle lighting. Just remember, the basic rules haven’t changed: be safe, be seen.