When the the nights draw in (or you get tempted by warm summer evenings to ride into the dark), you need to make sure you've got a set of lights on your bike. It's the law in the UK to run them after dark, and they're a major safety aid about town as well as letting you see where you're going in the dark lanes.
If you're in the market for some bike lights there's a bewildering array to choose from, at prices ranging from a few quid to nearly a grand, so what's the best bet for your riding? To help you choose, here's the road.cc quick guide to the technology and the options available for your front light.
Our beam test comparison data contains beam shots and data for 36 of this year's cycling front lights, as well as all our historical data going back to 2015 so you can directly compare one with another. As at the time of writing we've only just published the 2021 beam test, many of the lights included have not yet been reviewed on road.cc. The beam test will show you how they performed in terms of light output and the beam pattern, but it's important to note that there's more to a light when judging its overall performance. After the beam test, you'll find a guide to various options in lighting technology and some of our top light recommendations to date.
If you have a nice big screen you can click here for the widescreen version (1400x1000px)
We've collected lots of beam data so you can compare and contrast the different lights. Light manufacturers use a number of different metrics to describe light output. We've used lux here, but measured at a number of points across the width of the beam. That gives an indication of the brightness of the beam at the centre, the amount of peripheral light and the throw of the beam. We think that's the most useful measurement to directly compare. Specifically, we measured the lux value of the beam at two metres distance, in 10cm increments from the centre of the beam to 1m from the centre, giving eleven readings.
We've also included data on the shape of the beam. We've tried a number of different approaches to this in the past, but this year we've taken a picture of each beam with the camera in the same position, so you can compare the beam shapes directly.
Most of the lights we tested still had a more-or-less round beam. For riding on the road a more horizontal or squared-off beam has advantages. You're not wasting your battery lighting up the tree canopy, and you're less likely to dazzle oncoming traffic. Such beams are widely used in Europe, and in Germany they're the only lights legal for use on the road. Three of our 2021 lights have a StVZO (the German standard) compliant beam, although other manufacturers such as Lezyne do produce the lights, but don't sell them over here. We'd like to see more of them: they work well for a lot of road riding.
To get a good idea of what each beam looks like, we set up a bike on a rig so that we could photograph the beams of all the different lights in a comparable way. Each of the beam shots was taken using the same settings on the camera: 28mm (effective 45mm), shooting for 1s at f29 on ISO6400. If you fancy doing some of your own. So as much as they can be, they're directly comparable to one another. If one looks brighter than another, that's because it was. Matt the reflective-coat-sporting model is at 10m (the cones are 2m apart) and the car is 20m away.
The graph displaying the beam data uses a logarithmic scale to display the output of the lights. If you understand or care about such things, here's why:
Firstly, light beams follow an inverse square law regarding the strength of the light at increasing distance, because they're illuminating a two-dimensional plane. So at twice the distance, the light beam is spread over four times the area. Consequently, a light that is measured as twice as bright at its centre won't let you see twice as far. The logarithmic scale produces a more realistic visual comparison because of this.
Secondly, the variations in the amount of peripheral light, though much smaller than the variations in the centre, make a big difference to how much peripheral vision you get. The logarithmic scale amplifies these differences relative to the centre of the beam, so it's easier to see which unit is putting out more light at the sides.
A few years ago you had a choice of different bulb options to consider, but LED lights have improved to such an extent – and come down in price too – that there really isn't a choice any more. LEDs tick all the boxes for a bike light. They're tiny, they cost tuppence to make, they last for ever, they're rugged, they run fairly cool and they're easy on the juice. No wonder that everyone's using them these days.
There's LEDs and there's LEDs though. The bulbs in a cheap flasher that look like the ones out of your old 100-in-1 science set are a long way removed from the high-spec emitters in top-dollar off-road lamps. Outputs have shot up in the last couple or three years as well, with the brightest lights claiming outputs of several thousand lumens, more than a car headlight. More general purpose lights range from 400 to about 1000 lumens, with basic commuter lights and emergency lights weaker than that; they're mostly to be seen by, though, not to see with.
Technically, all bike lights must be fitted to comply with the Road Vehicle Lighting Regulations (RVLR). For the record, here's what those regs say:
One is required, showing a white light, positioned centrally or offside, up to 1500mm from the ground, aligned towards and visible from the front. If capable of emitting a steady light it must be marked as conforming to BS6102/3 or an equivalent EC standard. If capable of emitting only a flashing light, it must emit at least 4 candela.
One is required, to show a red light, positioned centrally or offside, between 350mm and 1500mm from the ground, at or near the rear, aligned towards and visible from behind. If capable of emitting a steady light it must be marked as conforming to BS3648, or BS6102/3, or an equivalent EC standard. If capable of emitting only a flashing light, it must emit at least 4 candela.
You also need a rear reflector and four pedal reflectors to fully comply with the RVLR.
In practice, not all bike lights are kitemarked. The specification for lights dates back to 1986 and is designed to apply to lights with filament bulbs. That doesn't mean that LED lights can't meet the requirements – many do – but lots of them aren't specifically tested for the ageing British Standard, especially those that are for the worldwide market. Since the RVLR were amended to allow cyclists to fit flashing LEDs we've heard very little about cyclists being stopped for having non-compliant lights.
What am I going to use the light for?
Are you going to be pootling down to the shops, or do you detour through the woods on the way home? You need to consider how much light you need, and where you need it to be put. Brighter is often better, but look for lights with good side visibility if you're riding a lot in town: side visibility is very important when coming out of a junction.
If you're solely riding on the road, look for a light with a beam pattern that's not going to dazzle oncoming traffic. Narrow beams and German-style cutoff beams (designed to comply with German road lighting regulations, where 95% of the available light must be directed downwards) are ones to look out for, although the German-style lights are still quite rare in the UK. If you're mixing up your road riding with paths and singletrack, a light with a wide beam that has lower-power modes for use in traffic may be the one to go for.
If you're going to be doing a lot of swapping between bikes, consider how easy that's going to be. Are the mounts quick release? Are there lots of wires to deal with?
How regularly will I use the light, and how long per day?
If your commute is an hour and your light gives out after 50 minutes then you're in trouble. If it has a proprietary charger rather than batteries or a USB charge option, then it needs to last to where you're going and back again. Think about when you'll recharge the light and how long that will take.
Many lights have low-power options that will extend battery life, so it's important to work out if these will give you enough output for certain sections of your ride. Many lights have fuel gauge displays to let you know the state of the battery, these can be very useful if you ride regularly and aren't good at remembering to charge your lights.
What conditions will I use the light in?
If you're riding every day, come what may, your lights will take a beating. They're very exposed to rain and spray at the front of your bike. Generally the more expensive lights are better constructed with more effective seals, so spend as much as you can afford. If you think you might break your lights from using them in all conditions, check what the warranty is like.
Okay, so you've got to buy some lights. What kind of lights do you need? Here's a quick run down of the basic types you can get your hands on, and who they're aimed at. We've mostly recommended lights for which we have a full review. For brand new models, take a look at the beam comparison engine, above.
Small enough to leave in your bag for when you need them, emergency lights normally attach with a stretchy band to the bars or frame and are powered by CR2032 button cells. They don't put out a great deal of light but as an get-you-home solution if you get caught out or your main lights fail, they're a lot better than nothing.
USB-rechargeable lights have dropped in price over the last couple of years, so if you don't fancy paying for a pair of CR2032s every now and then, you can get tiny lights that'll plug into your office computer to charge, like Cateye's Orb.
The next step up is a more powerful bar-mounted lamp. These are still lights to be seen by rather than for seeing, though most put out enough light that you can still make slow progress along unlit, well-surfaced trails and towpaths. There's almost always a flashing mode on offer too, though we'd advise discretion in its use. The pulse from even a low-power light can be bright enough to be aggravating to other cyclists, so best stick to steady mode on two-way bike paths and trails.
Of the latest batch of lights we've beam-tested only the Oxford Ultra Torch runs off separate batteries; almost all front lights in this category are now USB-rechargeable. That means the running cost is effectively zero, but it does mean that if you run out of juice you can't just nip into a service station and grab replacement AAAs.
Vel 300 — £24.00 (read review)
Exposure Sirius DayBright — £90 (read review)
Exposure Diablo MK12 — £215.00 (read review)
Exposure Joystick MK15 — £135.00 (read review)
Cateye HL-EL135 — £17.99
Lezyne KTV Drive 200 — £20.99 (read review)
Moon Meteor-X Auto Pro — £25.99 (read review)
Magicshine Allty 300 — £18.99
Cateye Volt 200 XC — £22.00
There's lots and lots of choice when it comes to larger torch-style cycling front lights. Powered either by either built-in rechargeable batteries or a swappable battery pack, they put out a bit more light. If your riding takes you anywhere you need to see – rather than just be seen – you'll need at least one of these.
Often manufacturers will bundle a torch-style front light with a rear flasher, seeing to both ends of your bike and scoring you a bit of a discount in the process.
Rechargeable units sometimes come with a mains adaptor but USB chargers are the majority, allowing you to juice up your light at your desk or just use another of your collection of wall-warts.
The brightest torch-style lights now kick out over 1,000 lumens, which is more than you'll ever need for road riding, but on lower settings the best ones will run all night.
Magicshine Allty 1000 — £69.99 (read review)
Lezyne Micro Drive Pro 800XL — £58.49 (read review)
Cateye AMPP 800 - £84.99 (read review)
ETC Kochab 1000 — £62.95 (read review)
Magicshine Allty 1500 - £89.99 (read review)
Ravemen PR1600 — £110.48 (read review)
Moon Meteor Storm Lite — £55.99 (read review)
Lezyne Macro Drive 1300XXL — £58.49 (read review)
Blackburn DayBlazer 1100 — £61.89 (read review)
Lezyne Super Drive 1600XXL - £120 (read review)
Cateye Volt 1700 — £115.49 (Read review)
Ravemen PR2400 - £199.99 (read review)
The most powerful cycling front lights tend to be characterised by a separate battery pack attached to a smaller head unit that's a lot more powerful than a standard torch. They start at around £20 for a CREE-powered eBay light but you can pay the best part of a grand for the really high end stuff. The big advantage of these systems is that you can swap the battery pack if you're doing a very long ride, and some manufacturers offer a range of battery packs. If you want to go out regularly and train after dark on the lanes, or venture off-road, then a battery pack system may be your best bet.
If you want your lights to be a permanent fixture and never worry about batteries then you can't do better than a dynamo. Hub dynamos are the pick for low maintenance and decent output; most will supply 2.4-3W which is plenty for a bright light front and rear. Pick a system that stores some of the energy from the dynamo so you don't go dark when you're stopped at the traffic lights. Many riders leave their dynamo lights on for daylight running too, as they draw very little energy from the bike.
Fitting a light to your helmet means you can point the beam where you want it, making the light a lot more useful. Some of the smaller rechargeable systems come with a helmet mount, or you could go for a more general use headband-type light and ziptie it on. Bear in mind that you should also have a fixed light on your bike if you want to comply with the law.
The aim of road.cc buyer's guides is to give you the most, authoritative, objective and up-to-date buying advice. We continuously update and republish our guides, checking prices, availability and looking for the best deals.
Our guides include links to websites where you can buy the featured products. Like most sites we make a small amount of money if you buy something after clicking on one of those links. We want you to be happy with what you buy, so we only include a product in a if we think it's one of the best of its kind.
As far as possible that means recommending equipment that we have actually reviewed, but we also include products that are popular, highly-regarded benchmarks in their categories.
Road.cc buyer's guides are maintained and updated by Mildred Locke. Email Mildred with comments, corrections or queries.
Dave is a founding father of road.cc, having previously worked on Cycling Plus and What Mountain Bike magazines back in the day. He also writes about e-bikes for our sister publication ebiketips. He's won three mountain bike bog snorkelling World Championships, and races at the back of the third cats.