LAST UPDATED 26 August 2019
Your bike must be fitted with fully functioning, switched-on front and rear lights when you ride after dark on public roads. This makes sense. It’s also the law in the UK.
But when bike light prices can range from under a tenner to £399 each, you might be looking for a steer on which bicycle light(s) to choose - hence this handy guide.
Bike light brightness is measured in lumens
A lumen is today’s standard measurement of light output. While the lamp’s build quality and the angle of its beam will influence its output, it is safe to make the assumption that while even a 5-10 lumen bike light will get you seen, a 50 lumen light will make you more conspicuous, especially from a distance. Similarly a 1,000 lumen front light will reveal more of the road/path ahead than a 500 lumen lamp.
You ride solely in town under streetlamps.
You can get by with a set of ‘be-seen’ lights. A be-seen front lamp barely illuminates the path or road ahead. However it does fulfil a bike light’s primary function of getting you seen by other road users after dark.
Be-seen lights, such as these sub-£20 sets by Cateye are the least expensive to buy and will do the trick on lit roads. Read our Best Bike Lights under £50 for more recommendations.
If you ride mostly in town but sometimes on unlit sections such as canal towpaths, you'll need a beam to keep you on the right track (perhaps literally) and alert you of impending potholes.
To that end, we would recommend a front lamp with at least 100 lumen output. For more staff recommendations on bike lights, read our blog.
You sometimes ride out of town, on road or off road, perhaps for commuting, maybe for exercise, always (we hope) for fun.
You won’t regret upgrading to a more powerful 400-1,000 lumen front lamp.
A headlamp this bright lets you see well ahead, and gives you early warning of broken tarmac, loose gravel, broken glass and so on when road riding. It should also be bright enough to light up blue/red-grade mountain bike trails - especially if matched with a decent head torch.
If you are looking for an especially well made front lamp with this kind of output, we heartily recommend you browse our Lezyne range, every one with a tool-free rubber strap fitting for easy interchangeability between bikes.
You appreciate having the trails virtually to yourself (or selves) after dark. You a mountain biking night rider.
One of the 400-to-1,000 lumen ‘rural riding’ lamps just described may well suffice for off road riding. If you’re into more adventurous / faster riding, bombing round red/black routes or exploring Highland glens or Yorkshire Dales, you’ll be amazed by the searchlight-like power (up to 2,000 lumens) of the latest Exposure lights – every one, CNC machined in Sussex.
New developments in bicycle lights
COB Lights by 'Moon'
Pioneered by Moon, COB technology has taken the be-seen LED bike light to a new level. COB means Chips On Board. Instead of relying on a single or a few individual LEDs (Light Emitting Diodes), a COB light has a strip of up to 30 LED chips to create a noticeably brighter light.
Like Lezyne, Moon lights are USB rechargeable and feature robust rubber fittings for fast interchangeability between bikes.
One of the benefits of these wonderfully efficient COB lights is they offer a Daytime Flash Mode option. As the name implies, this is bright enough to be seen in daylight. Smarter still, it pulses comparatively slowly (around once a second) so Daytime Flash doesn’t prematurely drain the battery. Offering up to 25 hours burn time per USB charge, there’s really no reason not to use these lights whenever you ride.
While it’s empowering to light the road or trail ahead with 1,500 lumens, its daft and it’s wrong to blind oncoming pedestrians and traffic. Take advantage of the fact that today’s brightest front lights make it easy to click between high and low power as conditions dictate.