road.cc front bike lights Beam Test 2023 — our big Beam Comparison Engine is live to help you choose the best front light for your riding

Here we go again! the clocks have gone back in the UK, it's dark before teatime and we’ve flipped the switch on the latest version of our famous(ish) road.cc front light Beam Comparison Engine to help you choose from the best bike lights (or more specifically the best front bike lights) for your riding.

The above video is from 2022, but all the info is still relevant

The big Beam Comparison Engine: an introduction

The beam test is now an annual tradition at road.cc Towers, which sees Dave and Oli head to a pitch black country lane with Manny the mannequin to get photographs of all the beams in the test, before Dave locks himself in the shed for a few hours to plot shapes and make some graphs.  

Our beam test comparison data contains beam shots and data for 43 lights this year, and also includes historical data going back to 2015. That's quite a lot of lights, so you can directly compare hundreds of lights with one another. After it, we'll take a brief look at the various options in lighting technology and explain how we collect and express the data.

If you're looking for more detailed recommendations, be sure check out our guides to the best front bike lights and best bike lights (front and rear) with more buying advice and links to reviews of all the products that have made it in. While our reviewers reference the beam test where possible and compare to similar lights when scoring, beam shape and brightness isn't the be-all and end-all, and it's important to consider other practicalities like run time, modes, size, mounting etc. Between this feature and our buyer's guides, hopefully there's plenty of info to help you make a more informed choice before choosing your ideal front light. 

...anyway, back to the beam testing. If you have a nice big screen you can click here for the widescreen version (1400x1000px)

This year's lights – what have we learned?

Although some manufacturers, Exposure for example, tend to update their lights every year, there are plenty of lights in this year's selection that are a few years old. Cateye and Ravemen both have lights that are still current and have been in the range for at least three years. There's nothing wrong with that, they're good lights. The Lezyne range, on the other hand, is all new, but now that they've been updated we'd expect them to stay as they are into 2025.

We've got some enormously powerful lights in this line-up, but really they're for off-road use and not designed for your road bike. At the top end of road (or all-purpose) lights, about 2,500 to 3,000 lumens is where we're at now, and that's more than you'd ever need for a road ride. I'm pegging the optimum high beam for a road light at no more than about 1,600 lumens, especially if the light features a lens that flattens off the beam so less of it is going into the sky and more on the road.

Every year there are some "German beam" SvTZO-compliant lights in the mix; this time it's the Trek/Bontrager lights, but we still can't buy SvTZO lights from the likes of Cateye and Lezyne, who make them for the European market but don't bring them into the UK. They're a bit more widely available in the UK now, but they're still not that common. More likely your bike light will either have a basic round beam, or it'll use some kind of refractive lens to shape the output a bit and maximise the illumination. Exposure, Ravemen, Gaciron and Moon all have lights with refractive lenses.

LED technology and battery technology continues to improve incrementally behind the scenes, and the improved efficiency means improved runtimes for the same output. These days it's not hard to find a small torch-style light that'll run all night, on a beam setting that'll allow you to ride at a decent pace. If you'd offered 25-year-old me that when I was getting about an hour of usable light out of my Lumicycle system with its chunky battery pack and bulb straight out of your bathroom ceiling, I'd have bitten your hand off. 

> Do you remember Ever Ready bike lights? 

As we've said for a few years in a row now, the trend is still heading towards brighter and brighter lights; or at least, the most powerful settings on a lot of our selections are super bright, and more than you'd ever need on a road ride. 

The move to USB-C from Micro-USB for charging is continuing to gain pace, with almost all the brighter lights now charging with USB-C. Shorter charge times, a double-sided design and more widely-spaced contacts arguably makes USB-C better than Micro-USB for charging bike lights, so this steady evolution is a welcome one. 

How we collect beam data

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 compare directly. 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, by taking a picture of each beam with the camera in the same position. Wider beams should appear wider, and if a beam isn't round you should be able to see what's going on with the shape.

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. They're as directly comparable as they can be. If one looks brighter than another, that's because it was. Manny the high-vis-wearing mannequin is at 10m (the cones are 2m apart) and the car is 20m away.

Although we use the same piece of road every year, it's very hard to make the beam shots directly comparable to other years. If the road was particularly wet in one year, for example, that means less reflected light from the surface compared to a drier year, making the lights appear darker. So the only directly comparable shots are the ones taken in the same year. 

A word about logs

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:

First, 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.

Second, 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.

And finally…

As we've already mentioned, bear in mind that having a very bright beam isn’t the whole story when it comes to deciding how good a bike light actually is. There are loads of other factors to take into consideration when it comes to finding the best light for the cycling you do, such as runtime, durability, ease of recharging, weather sealing, how good the clamping mechanism is etc, etc. It is a start, though.

Any of these lights we haven't already reviewed in full will be getting sent off to road.cc reviewers very soon. Our road.cc light beam comparison engine is pinned to the top of our features section, and lives on the road.cc homepage throughout the winter. It's also linked in both our best bike lights and best front bike lights buyer's guides.