The products mentioned in this article are selected or reviewed independently by our journalists. When you buy through links on our site we may earn an affiliate commission, but this never influences our opinion.

Cateye Rapid X3 rear light review

How does Cateye’s Rapid X3 fare out on in the mud and slop?

Our rating 
3.5 out of 5 star rating 3.5
GBP £50.00 RRP | USD $60.00 | AUD $100.00

Our review

A good light with plenty of functions and more than ample power. It could do with some alternative mounting options
Pros: Great power; loads of modes with twin-LED operation
Cons: Mounting options are limited and cause the light to move more than other rear lights
Skip to view product specifications

The Cateye Rapid X3 is the Japanese company’s most powerful rear light, with a claimed maximum output of 150 lumens and a run time of an hour on that headline setting.


It’s incredibly bright, while a range of less powerful (and more economical) modes are also available, but mounting options are limited.

Cateye Rapid X3 details and specification

Cateye Rapid X3
Its long and thin form factor might not suit some bikes.
Alex Evans

Like a lot of other lights on the market, the Rapid X3 has a long and thin profile, which is best suited to mounting on vertical tubes such as frames and seatposts, and is secured using a rubber O-ring.

The Rapid X3 has an integrated, changeable rubber mount that, when removed, reveals the USB charging port.

The twin COB-style LED is powered by a Lithium-ion battery offering up to 150 lumens in the most powerful constant mode.

Cateye Rapid X3
There are a lot of potential modes on the X3.
Alex Evans

All in all, there are three constant modes and three flashing settings that are cycled using two buttons — one for each set of COB LEDs.

There’s a low-battery and charge indicator, and the light has mode memory so it remembers the last-used mode when you turn it on again.

Cateye Rapid X3 performance

The Rapid X3 is easy to mount using the supplied O-rings, but the shape of the swappable mounting pad means that the light can flop from side to side if knocked or vibrated particularly vigorously.

It is quite deep and narrow and the problem persists with even the widest mount fitted.

COB led rear light for mountain bike
It sticks out a fair amount which could result in contact with the tyre as the bike’s suspension bottoms out
Alex Evans

This makes the light perch on the tube it’s mounted to rather than envelop it into the deep recess. If knocked, the light moves and doesn’t return to the position it was set in.

The deep profile of the light’s body means that it sits quite proud from the tube when it’s mounted. This is accentuated when an even narrower mount is used because it sits on top of the shallower one.

Its depth means that it’s particularly exposed to knocks from the back wheel on suspension bikes during bottom-out too.

Cateye Rapid X3
The USB port is covered by the light’s mounting surfance and is fairly exposed to dirt and grime.
Alex Evans

It can only be mounted vertically with the options supplied out of the box, and the two buttons are on either side of the light, controlling their respective COB LEDs.

Their side location gave me hope they’d be easy to operate on the move but the buttons are hard and stiff to push, with little travel making operation of the light quite tricky.

Cateye Rapid X3
The Rapid X3 has two buttons that control two banks of LEDs.
Alex Evans

There are a lot of different mode possibilities thanks to the individually operated LEDs that have the same number of modes each, and I think you’d be hard pressed to not find a mode that suits your needs.

Although there’s a good number of modes on offer and their selection is relatively straight forward, it’s a pain to have to operate both buttons all the time. It would be better if the light had a feature where the two buttons were synced and operated by only one of them.

Cateye Rapid X3
The buttons are quite fiddly to use.
Alex Evans

The light’s power projects rearward impressively and lights up the floor with a nice red hue. I was impressed with the amount of power on offer.

Side illumination is good up to about 70 degrees from the rear, tailing off considerably from 80 degrees up to 90, relying almost entirely on the light’s brightness rather than any specific beam projection.

Run time on max is one hour, the same as Cateye’s claims. The light is bright, so it’s no surprise that it doesn’t last as long as other lights on the market and with the number of modes on offer it should be easy to eke out more life from the battery.


Cateye Rapid X3 bottom line

A good light with plenty of functions and more than ample power. It could do with some alternative mounting options, though.

Product Specifications


Price AUD $100.00GBP £50.00USD $60.00
Weight 45g – Total weight
Brand Cateye


Features Clamp weight: 5g
Light weight: 40g
Run time (max power): 1 hour
Integrated battery Yes
Light type Rear
Output (lumens) 150
Remote switch no