See and be seen with our top front bike lights for on the road, trail or path

Do bikes need front lights?

To get the easy one out the way first and to answer the first question on the ‘people often ask this’ bit on Google (sorry, it’s considered best practice)… yes! In most countries it’s the law – or at least highly recommended – to run front and rear bike lights after sunset and before sunrise. Here in the UK, it’s a legal requirement for your bike to be fitted with a white front light and red rear light when cycling at night. 

What else does the law say about bike lights? Are flashing lights legal?

In the UK, 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:

Front Lamp
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.

Rear Lamp
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. 

While in a lot of places the general rule is that front and rear bike lights are mandatory, the regulations can differ in other territories. In Germany, for example, the front beam needs to be StVZO-compliant, which means they have a beam that is cut off to avoid dazzling other road users. These beams are often square rather than round, and the rules also state that the light must be constant and not flashing. This is because flashing or pulsing lights are distracting, according to the StVZO rules. 

If flashing front beams are road-legal where you live, like here in the UK, then you might feel like you’re more noticeable with this setting compared to a steady light – ultimately it’s up to you. Cyclists who use daytime bike lights often use flashing settings, but at night where you also need your beam to light the road/trail ahead of you as well as catch the attention of drivers, we’d usually recommend a constant beam setting. 

What is the best headlight for a bike?

As you might have guessed, there’s no right answer here and it will depend on where and when you ride, but there will be wrong answers if you’re currently running a light that’s largely unsuitable. 

To avoid this, 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?

What are the different types of front bike lights?

Here’s a mini-guide to the different types of front bike light out there…

Emergency lights

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.

Small torches

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.

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.

Torches

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.

Battery pack systems

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.

Dynamo lights

If you want your lights to be a permanent fixture and never worry about batteries, then a dynamo is your best option. 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.

Head torches

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 in the UK. 

How many lumens do I need for a front bike light?

Front bike lights come in two categories: those designed to help you be seen, and those intended for illuminating your path.

If you’re using your front light at night to see where you’re going, look for outputs of about 500 lumens and up. We’ve found that for riding on unlit off-road paths, somewhere around 800 lumens depending on the shape of the beam is ideal – but of course, if you encounter other cyclists or pedestrians coming towards you, then make sure you’re able to dip your beam or change to a much lower setting to avoid dazzling them. 

The same goes for riding on the road at night. A ridiculously bright front beam doesn’t necessarily mean safer, because it could dazzle other road users. If in doubt, get friends or family to take a look at your light from a distance. We all have different tolerlances to bright lights and visual acuity, but it doesn’t hurt to get some consensus. 

For mountain bike/trail riding, you’ll probably want an even brighter beam with thousands of lumens, because there’s a lot more potental hazards that you need to pick out on technical trails compared to cycle paths, shared use paths or unlit roads. 

What's the difference between lumens and lux?

In short, lumens is the total amount of light emitted from the source in all directions, while lux measures the total amount of light that falls on a surface, taking area into account. To give a brief example, if you shine a beam that has a total of 1,000 lumens at the wall, at its max brightness but on a setting where the beam spreads 80 degrees wide, there will be far less lux on the wall than if you had the same brightness but with a beam that spreads 40 degrees wide. It’s because of this that we use lux in our Beam Comparison Engine, measuring the lux value of the beam at two metres distance, in 10cm increments from the centre of the beam to 1m from the centre, which gives a total of eleven readings.

To clarify: most brands will advertise how bright their lights are using lumens and this is a decent indicator of how bright they can be, but it doesn’t tell the full story.

What is the best mounting system for front bike lights? What if I have aero handlebars?

This will depend on your bike and personal preference of course, but there are a few things to consider. Firstly, will your bike light live permanently on one bike? If so, then you can use a light with a secure bracket and remove the light when you need to charge it. Most road handlebars are 31.8mm in diameter, but there are still smaller and larger clamp sizes out there. Some light brackets cater for multiple diameters with inserts, but it’s worth checking in the product description that the bracket is compatible with the size of your handlebars.

It’s also worth thinking about what else you plan to put on your bars. If you plan on running a light, computer and a camera, things could become cluttered or not fit at all, so you could consider an all-in-one solution to mount them together. There are a number of aftermarket solutions for mounting lights, cameras and computers – or a combination of the three – to accommodate products from numerous different brands. You can check out our reviews of computer mounts for some examples. 

With a flexible rubber mounting system, Lezyne’s Strip Drive lights can fit around most non-standard handlebars

If your handlebars aren’t a standard shape or you want to move your light between bikes regularly then your options are more limited, but there are options out there. In both scenarios you’ll probably want to steer clear of lights that slot into separate mounts that are fixed onto your bars. Brands such as Knog and Lezyne offer lights with very flexible rubber mounts (front and rear), with Lezyne’s Strip Drive able to mount onto most aero-shaped/non-standard handlebars. If you run Exposure lights, the brand offers a silicone band to attach its lights to most aero-shaped handlebars.