Most rear bike lights do one thing at one brightness and hope for the best. The TraceR 4 ReAKT pays attention. It flares up when you brake and when the light around you gets brighter, then eases off for the rider sitting on your wheel. All of that comes from a 38g package delivering up to 200 lumens, charged over USB-C in 90 minutes. A CNC-machined aluminium body and IP67 rating mean it shrugs off a British winter. Pair it with the Trace 4 front light and you are properly visible, day or night, at either end of the bike.
In the box:TraceR 4 Reakt , Seatpost Bracket, USB - C Charge Cable.
A single press of the power button while the light is off displays the battery level for five seconds, providing a quick and convenient way to stay informed and prepared for every ride. This battery status is also displayed when the light is turned off.
Size
Engineered with a sleek, adaptable form factor, it integrates effortlessly into any environment while providing exceptional performance on demand.
Side visibility
Our optically clear 270° Commute Lens enhances side illumination, ensuring you stand out from every angle on the road. Whether you’re navigating dark paths or city streets, this setup delivers maximum visibility, safety, and rider confidence.
Weatherproof
Class leading waterproof ratings mean you will never be let down in any situations, and you can always depend on your light
Weight
Delivers up to 40 hours of runtime from a product weighing only 38 grams with no compromise to strength or durability.
Engineering
Our CNC-machined 6063 aerospace-grade aluminium body is built to withstand the toughest conditions, with a scratch resistant polycarbonate front lens this light is designed to withstand all that you can through at it
Daybright Flash
Our bespoke DayBright pulse pattern is specifically designed for daylight use, making it more conspicuous than a standard pulse and visible over a kilometre away, even in the brightest conditions. With DayBright mode, you’ll be noticed. Be Seen, Be Safe.
USB-C Charging
Offers fast and convenient USB-C charging, allowing you to power up quickly and get back on the road without delays.
OUTPUT
WHATS IN THE BOX
Frequently asked questions
ReAKT is Exposure's reactive light technology. It automatically increases the TraceR 4's output in two situations: when you brake, and when the ambient light around you gets brighter.
Braking gives the vehicle behind an instinctive signal that you are slowing. The ambient light response keeps you visible in bright sun and low winter glare, which is exactly when a fixed-output rear light struggles to stand out.
It works on its own, with nothing to press while you are riding.
Peloton mode senses the light of a rider following you and automatically reduces the TraceR 4's output to avoid dazzling them. It is built for club runs, chaingangs and group riding, where a bright rear light is genuinely unpleasant for whoever is on your wheel.
ReAKT and Peloton do not run at the same time, and you can switch either on or off depending on how you are riding that day.
Comfortably, yes. Rear lights work differently to front lights: the job is being seen, not seeing.
200 lumens in DayBright pulse is bright enough to stand out in daylight, while 75 lumens constant suits lit roads after dark. More output is not automatically better on a rear light, which is precisely why Peloton mode exists.
We offer an extra year warranty to all purchases made through our site. This means you will have 3 year warranty on all of our lights and the LED’s inside are covered by a lifetime guarantee! Ensuring peace of mind with every purchase.
Our lights are designed to last a lifetime, so we carry out servicing and repairs on lights well beyond the warranty period - simply get in touch if you ever need us - we've got you covered!
I have been using these (and the Exposure head torch) for about twenty years. They are lightweight, have good luminosity and last a full day’s ride. Good to buy British and no need to look elsewhere.
The Trace+ and TracerR ReAKT light set is highly effective. The illumination is surprisingly powerful for such a small product. The build quality and the materials used are excellent. Impeccable.
I purchased this rear bike light for my adult son for his birthday.
I do not have any photo's but he us extremely happy.
He had purchased lights previously but they were not as advertised having false Lumin claims and poor build quality.
These by contrast were exactly, came as advertised with excellent build quality and accurate lumin beam.
Brighter than the previous model and uses a “C” connector for charging versus the “Mini USB”.
Easier connection and faster. A little complicated to program the various modes. I printed a hard copy of the instructions to help me.
Increases visibility. I like the helmet mount so I can point the front flashing white light directly at motorists. One more safety item to go along with radar and a helmet mounted mirror. The older I get the less I want to die.
This is a little light that performs splendidly. It's easy to operate, with gloves on or off. It's got a seriously long run time at the lower power levels despite it's tiny size and is almost dazzlingly bright at full power. I've not had cause to use the tech settings yet but they should be really useful when necessary. A great piece of kit.
Been using these for years, hands down the best bike lights. If anything goes wrong they will fix them. I had to buy a new one as I sadly lost one, if you’re less careless than me they’ll last you for years.
Put these on my bike for a long weekend in Mallorca. They lasted on pulse mode across four days of riding without needing a single charge and were light enough not to notice them on the climbs. Great bit of kit for being seen - especially through the occasional tunnel!
Great rear light.
Only improvement I would make would be to add a safety cord similar to the helmet lights which could be wrapped around the seat post. I use it on my mountain bike so it would take away the worry of losing it on trails.
This is my third set of these wonderful little Exposure lights - I still use my >10 year old Flash/Flare set on occasion and wanted a new set to replace my not quite as elderly original Trace/Tracer with a micro USB socket. Everything else I use now has type C, so I managed to self-justify the upgrade.
Still the same tiny size, epic build quality, simplicity of use (just set and forget) and ridiculous burn times from something so small. And they all fit in the same mounts, so dead easy to move about.
One on the bar and the other on the back of my helmet every time I hit the road and/or gravel trails.
They are just a normal part of my kit in the same way my helmet and gloves are. Never leave home without them! Now I don't actually have to keep swapping them bewtween bikes either.
Daybright pattern does exactly what it says on the tin - it gets you noticed from a very long way off regardless of the lighting conditions. Rather important if you dont want squished.
Flawless performance from all 3 sets and superb customer service should you ever need it (which only happened once when I managed to crack a Flash hood after a stack and they sent me two spare ones foc).
Love these lights and have never needed any of their bigger siblings yet.
They do appear expensive against some of the opposition but I believe you are getting the best value for money in the long run . They just keep working.
And they are a UK company...
Absolutely great little lights. I got them purely for being seen as the nights get longer and the days shorter. I must admit the one button UI is a bit weird, but it works.