Exposure has been a go-to brand for helmet lights for years. The UK company has never been the cheapest, but its vent-clamping mount is the neatest and arguably the best, and it’s won plenty of fans on the 24-hour race circuit and beyond with its reliable, well-thought-out lights. The Exposure Diablo MK11 continues that tradition.
As the ‘MK11’ in the name indicates, this is a design that’s constantly evolved. With its bulbous lens housing, it’s neither as slim nor as light as the £50 cheaper Exposure Joystick and, at 127g, can make less stable helmets wobble a bit, but it’s a lot more powerful, putting out a claimed 1,750 lumens on max.
The three white Cree XP-L2 LEDs produce an excellent beam, with a bright central spot that reaches a decent way into the distance, surrounded by a gradually dimming flood of light that doesn’t peter out until the limits of your peripheral vision.
Battery life on max is pretty much bang-on Exposure’s claim of one hour, although the first low-charge warning flash comes on after just 30 minutes or so, which is disconcerting the first couple of times it happens. An hour may not sound very long, but realistically you’re only going to need the full 1,750 lumens for descents and technical trails, and turning the power down on road, uphill and gentler sections ekes out significantly more life from the 3,400mAh lithium-ion battery.
If you need a longer run time, you can simply switch to another of the light’s eight power settings, each of which gives a choice of three modes (high/medium/low). With only one button, on the rear of the light, and no LCD screen, this is a slightly fiddly process – you have to turn the Diablo off, hold the button down, wait for some quick flashes, then release the button after the relevant number of slower flashes (one to eight).
Topping things off is Exposure’s TAP function, which lets you change modes by tapping your helmet or the light, instead of having to scrabble around for the button. Switching this function on or off and setting your desired level of sensitivity involves a complicated sequence of button-holding and tapping. Thankfully, this becomes more intuitive with time, although several times I thought I was back in button-only mode, only for the light to dim unexpectedly when I tapped it to double check.
Exposure also offers a SYNC version of the Diablo for £50 more (or £305 with a spare battery, remote switch and other extras), which changes mode automatically when it senses that you’re riding fast, thanks to internal accelerometers and a gyroscope. This is slightly more powerful too (1,850-lumen), but its run time is significantly shorter (40 minutes, claimed, on max).
Both use the same helmet mount, which is excellent. There are no Velcro straps or sticky pads here. Instead, the mount sandwiches one of your helmet’s vents between two plastic discs, connected by a plastic Allen bolt. It’s a simple and secure system, and two different-length bolts are supplied to fit different lids.
Be warned that it won’t work with helmets where the vents are filled with Koroyd or similar protective materials, and may give a lopsided feel on designs with no central vents.
I also found it roughed up the matt finish of some lids, but that’s a common problem with helmet mounts and is easily fixed by applying a little electrical tape before fitting.
The light simply pushes into a plastic clip on top of the mount, which is attached to a ball-and-socket joint for easy directional adjustment. This seems almost too easy, but despite the lack of retaining straps or O-rings, I haven’t lost an Exposure helmet light yet or had any problems with wobble.
A bar mount is provided too, and the Diablo is bright enough to be useful there off-road. Just make sure to turn the TAP function off first to avoid it dimming every time you hit a root.
Constructed from 6063 aluminium alloy, the light has a durable feel. It’s 115mm long and 41mm in diameter at its widest point. An IP6 water-resistance rating means it should shrug off rain and washes.
It charges via a USB port hidden under a rubber plug at the rear, in around four hours if you use the fast charger that’s supplied in the case, and comes with a small but comprehensive user manual.
Fiddly mode selection and relatively high price aside, this is a light that’s difficult to find fault with.