Cateye Rapid X3 rear light review

The Cateye Rapid X3 is Cateye’s top-of-the-range rear light, pushing out 150 lumens on its top power setting. It achieves this using twin arrays of chip on board (COB) LEDs.

COB is the latest LED tech, where the light-emitting LEDs form part of the chip rather than being separate components soldered into the circuit. Although the power of each LED is less, COB can achieve much higher LED densities resulting in a larger array for a given output.

Like other high-intensity rear lights, the Cateye Rapid X3 is a strip-shaped unit, attached to the back of your seatpost by a rubber band that hooks over a protuberance on either side of the light’s body. Side wings keep the unit pointing in the right direction and allow it to fit on aero or round seatposts.

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The Cateye Rapid X3 is essentially two lights in one body, each with its own on/off/mode switch. This gives you a lot of lighting options: for example, you can have one constant high intensity and one flashing LED array. With six different modes for each array, there are endless different combinations.

All the LEDs in each array flash simultaneously, giving a large area of illumination. There’s evidence that drivers find it easier to range a constant than a flashing light, so the option to have both is also a plus.

The highest 150 lumen output of the Cateye Rapid X3 is only achieved in the highest output constant mode. This reduces run time to just one hour. The four flashing modes produce fewer lumens: two at 30 lumens, one at 20 and the highest intensity rapid flash 50 lumens, but nevertheless are bright enough to be easily visible even in bright sunlight. There’s also a low intensity constant mode of 20 lumens with five hours run time.

Charging takes around three hours, with a USB cable plugging into a socket on the top of the unit, under a rubber bung. There is a mode memory function, so both lighting arrays will start in the mode which was last used.

You get a low battery indicator – not so useful when you’re riding the bike. But the unit also switches to a power-saving flashing mode when it starts to run down. With a claimed run time when fully charged of 30 hours, even with a depleted battery this should be more than enough to get you home – we reckoned it ran for over two hours after switching from the high intensity constant mode, which itself managed more than the headline one-hour burn.

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Run time for flashing modes varies between 8 and 30 hours, so battery life isn’t an issue. Although the headline flashing output isn’t as great as some other rear lights, the large array and option to mix it with other modes makes for a very noticeable rear light.

The translucent casing means that the Cateye Rapid X3 has good side-on illumination too, with the light visible from all angles not shaded by the seatpost. It’s a clever unit that punches above its headline outputs.