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Let there be lights! The road.cc 2019 Front Light Beam Comparison engine is live – helping you compare the beams of this year's top bike lights

We've beam tested 45 of the latest cycling lights so you can compare and contrast (sorry) their output… here's how we did it and what we've learned

It’s that time of year again, Sainos have been selling mince pies for a month, the clocks are about to go back, darkness is descending and here at road.cc we’re flipping the switch on the 2019 version of our front light beam comparison engine (hours of fun for all the family).

The light beam comparison engine

Our beam test comparison data contains beam shots and data for 45 of this year's lights, as well as all our historical data going back to 2015 – quite a lot of lights – so you can directly compare one with another. After it, we take a look at the various options in lighting technology and recommend some of our favourite lights.

If you have a nice big screen you can click here for the widescreen version (1400x1000px)

This year's lights – what have we learned?

Well, it still seems to a bit of an arms race a lot of the time. Taking insane lights like the Exposure Six Pack and Lumicycle Apogee out of the equation – those are really designed for off-road use – there are still plenty of lights that use an unregulated beam and plenty of firepower to get you going at night, more than is necessary (or welcome) on busy roads. beam shapes are getting more varied, though, with Exposure, Knog, Ravemen, BBB and more offering squatter, more road-focused beam patterns.

Of all the lights sent in this year, only the BBB Swat would be legal in Germany, using a SVTZO-compliant beam pattern. Other manufacturers – Lezyne is a notable one – offer lights with these cut-off beams in other European countries, but not here in the UK. It'd be good to have the choice for road riding. Other than that, lights are just incrementally improving: they're cheaper, or they run a bit longer, or they're a bit brighter, or a combination of those factors.

There's a move towards USB-C charging which offers shorter charge times, and a few manufacturers have been tweaking their brackets for a better user experience; a few this year have moved to a Garmin-style quarter-turn mount which opens up a wide selection of after-market mounting options.

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. Last year we switched to a new method for helping you see the shape of the beam by taking a picture of each beam with the camera in the same position and using the same exposure. We’ve stuck with that approach this year. Wider beams should appear wider, and brighter beams brighter.

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. Matt the Aldi-coat-sporting model is at 10m (the cones are 2m apart) and the car is 20m away.

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.

Beam comparison 2019 split screen

And finally…

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 in to 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. We’ll be bringing you the full story on these lights in our upcoming reviews of them (some of them are already live on the site. Our road.cc light beam comparison engine will be living on the road.cc homepage throughout the winter. You’ll also find it on the Front light page of our reviews section too and in the Front light buyers guide.

Tony has been editing cycling magazines and websites since 1997 starting out as production editor and then deputy editor of Total Bike, acting editor of Total Mountain Bike and then seven years as editor of Cycling Plus. He launched his first cycling website - the Cycling Plus Forum at the turn of the century. In 2006 he left C+ to head up the launch team for Bike Radar which he edited until 2008, when he co-launched the multi-award winning road.cc - which he continues to edit today. His favourite ride is his ‘commute’ - which he does most days inc weekends and he’s been cycle-commuting since 1994. His favourite bikes are titanium and have disc brakes.

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