Bigger and much brighter than previous Rapid X models, the new Cateye Rapid X3 rear light kicks out such a potent red glow on full power that you might think you could warm your hands on it. As with previous models from this range, it has outstanding visibility from the sides as well as from behind, making it a top choice for the busy urban environment. It's pricey, though, and you'll want to use the full-power mode sparingly if you're going far.
Last year's Rapid X2 was a more powerful version of the Rapid X that I tested previously, taking advantage of improvements in battery and LED technology to kick out more light than the original – a claimed 50 lumens. What Cateye appears to have done here for the new X3 model is simply stick two X2 lights together side by side, in a single package.
There are two separate LED strip lights now, and maximum output is lifted to a stonking 100 lumens. Unusually, the two strip lights are operated independently, each with its own button to select from the six available modes, giving a possible 48 different combinations (go on, maths pedants: I dare you).
Unlike some other premium rear lights, which use reflectors or collimated lenses to direct their light in a beam for maximum range, the Rapid X3 is a spread-it-around sort of light. As a consequence, you can mount it at any angle and it's highly visible, even from a side angle of more than 90 degrees. Using it, I felt pretty confident that other road users could see me from any direction, even in poor conditions.
The Rapid X3 is chunkier and weightier than the previous versions, obviously requiring more battery capacity to kick out that much light. It still sits neatly behind a seatpost, though, held in place with one of four rubber o-rings. It's a simple system but one that works well. It'll fix to a seatstay or rack tube too, using the smallest of the o-rings, and there's also an extra rubber skirt designed specifically for use on an aero seatpost. That's a nice touch as aero road bikes are becoming more popular and some lights simply won't fit their seatposts.
Cateye offers an optional Spacer X clip that allows you to attach the light to even more things, such as a bracket on a rack, a Fizik saddle clip or one of Cateye's FlexTight brackets. I didn't really see the need for this but others might.
Being able to choose a mode for each side allows you to combine two different outputs from a single light, to eye-catching effect. There are two constant settings, with the high mode giving 50 lumens per side versus 10 lumens for the low mode. If you set both sides on high then burn time is a measly one hour, so you'll only want to use that on short rides. That compares poorly to the likes of the Knog Blinder R70 (review coming soon) and Bontrager Flare R (review also coming soon, but for now you can read about it here), both very bright lights that can manage over three hours on constant full-power mode.
Cateye quotes battery life for each of the modes, assuming that both sides are using the same setting (see test report, below). The 30-lumen flash mode is good for 30 hours, and would presumably do twice that if you only used one side. Using only one side isn't a great idea, though, as it means that lateral visibility from the other side is greatly reduced. Using the lower constant setting on one side with a flashing mode on the other was my preferred option and gave enough juice for a week's commuting, which is my basic requirement of a rear light.
There are flashing modes of varying frequency and intensity, plus a pleasing pulse mode which is a bit gentler on the eyes – good for when you're riding with mates.
Operation is pretty simple: push and hold a button to switch that side on or off, and push it again to scroll through the modes. It's easy to operate both buttons together using one hand. Mode memory is always welcome on a light, especially with so many possible settings here. Switch it off, and it'll come back on next time with the same mode(s) that you were using previously.
The X3 has a lithium-ion battery which is USB rechargeable, via the ubiquitous micro-USB socket now located at one end. This sits under a rubber flap that seems to do a good job of keeping water out. I've used it in some pretty nasty weather with no problems.
When the battery is getting low, the light will switch to the flash mode to eke out what charge there is remaining, and one of the buttons will flash red. It'll still last for a good few hours in this state, so you should have plenty of time to reach a charger without being left in the dark.
I've used various models from Cateye's front and rear light range extensively over the years, and have had very few problems with them. This light gives you a lot of confidence that you'll be seen by other road users behind and to the side of you, and is among the very best rear lights I've used. At £55 it's not cheap for a rear light – you can get a decent rechargeable light for £20 nowadays – but in its price bracket this would be my first choice.
Fantastic all-round visibility from a neat package, though you won't get 100 lumens for long
road.cc test report
Make and model: Cateye Rapid X3 rear light
Size tested: 100 lumen
Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
The ultimate safety light.
The Rapid X3 represents the pinnacle of safety light technology, designed to ensure you're seen both day and night. Doubling the brightness of our popular X2, the X3 100 lumens in the rear. Featuring our most versatile system, the Rapid X3 easily mounts to almost any application, including round and aero seatposts, seatstays, handlebars, forks and headtubes. With the optional Spacer X accessory, the X3 fits our FlexTightTM, rear rack, saddle rail and Fizik saddle brackets too. Add the best side visibility in it's class, and you have the ultimate safety light.
Tell us some more about the technical aspects of the product?
Dimension: 74.0 x 31.0 x 39.0 mm
Weight: 46g (with batteries)
Light source: COB LED
Battery: Lithium-ion rechargeable battery
High mode (100 lumens): 1 hr
Low mode (20 lumens): 5 hrs
Flashing mode (30 lumens): 30 hrs
Rapid mode (50 lumens): 16 hrs
Pulse mode (20 lumens) :16 hrs
Vibration mode (30 lumens): 8 hrs
Recharge time: 3 hrs (USB2.0)
Mount size: Rubber band mount (fits f 12.0-32.0mm)
Other : Battery auto save, Low battery indicator, Light mode memory
Other lights in this price band arguably feel more premium, thanks to the use of aluminium instead of plastic. However, there's not much wrong with how this is put together and I'd argue that performance is what you're really paying for.
Superb visibility from just about any direction. Battery life is good on the flashing modes but an hour is pretty unimpressive on full power constant compared to the competition.
I've had no issues with the old Rapid X that I reviewed (and have continued to use regularly since) and I can't see any obvious weak points here.
Other less bright lights may weigh less, but I don't think that the weight of this is likely to be an issue for many people.
You can get a perfectly adequate rechargeable rear light for £20 so it would be hard to give this top marks. You do get twice the output that last year's X2 managed for only a third more money, though.
Tell us how the product performed overall when used for its designed purpose
Very well – it is my current favourite rear light.
Tell us what you particularly liked about the product
All-round visibility, neat package that's easy to swap between bikes, and a wide range of modes.
Tell us what you particularly disliked about the product
It would be nice to see a longer run time on the headline 100 lumen setting.
Did you enjoy using the product? Yes
Would you consider buying the product? Yes
Would you recommend the product to a friend? Yes
Use this box to explain your score
I reckon this is probably my favourite rear light on the market at the moment. It might not have the focused range of the likes of the Bontrager Flare or the Knog Blinder R70, but it more than makes up for it with better side visibility than either. Loses a star because of the 1 hour run time on max power, which is well down on either of these competitors.
About the tester
I usually ride: Commuter - something with disc brakes, drop bars and a rack My best bike is: Rose X-Lite CRS
I've been riding for: Over 20 years I ride: Most days I would class myself as: Expert
I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, touring, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking
Jez spends his days making robots that drive cars but is happiest when on two wheels. His roots are in mountain biking but he spends more time nowadays on the road, occasionally racing but more often just riding.