Product test
Garmin Varia – a smart light for your bike
by Patrick Bardelli
Small bike radar guide: which is best?
12/8/2025
Translation: Jessica Johnson-Ferguson
Pictures: Patrick Bardelli
Shine bright: smart radar tail lights for your bicycle give off a visual and acoustic alarm when a vehicle’s approaching from behind. Several brands feature these lights in their range, so I’ve put together a compact selection for you.
What’s a radar tail light even good for? Isn’t it just another one of those superfluous bike gadgets that costs an arm and a leg without actually doing much? While these questions are justified, my answer to the latter is no.
As for the first question, the idea behind the technology is to alert you if there’s a vehicle approaching from behind. To activate the alert, you pair the light/radar with your compatible bike computer, smartwatch or smartphone. Obviously, you can also see what’s going on behind you by mounting a simple rearview mirror to your helmet or handlebars. However, you may want the extra tech in some situations.
What, when, how and where?
Do you use your bike to get to work, for short rides with the family or to dash into town to meet friends in the evening? If so, a rearview mirror in addition to your rear light should do the trick (here’s all you need to know about the rules and regulations regarding bicycle lights).
However, if you regularly cycle for exercise purposes, the radar function might be of interest to you. In my opinion, there’s one massive drawback: the radar’s useless in road traffic. In fact, it’s distracting. There’s always something going on behind you when you’re cycling on busy roads, so the constant visual and acoustic alarms become really annoying after a while. Away from busy roads, however, the benefits of the radar really come into their own.
Here’s a brief overview of the most important suppliers in our range:
Garmin Varia RTL515/516
The true pioneers. Launched around ten years ago, the Varia from Garmin was the world’s first radar system for bicycles. Since then, the US-based company has continued to develop its system. I tested the OG a few years ago. Here’s what I thought of it:
Garmin Varia RCT715
The radar tail light is now also available with an integrated dashcam. I reviewed this one, too, and here’s what I thought:
Keep in mind that using the built-in dashcam is a bit controversial from a legal perspective. It’s still unclear if the images it records would be accepted as evidence in a court case.
Bryton Gardia R300
The Gardia R300 L from Bryton is a product that impressed me with its value for money. Here’s my extensive test review:
Magicshine Seemee R300
The Seemee R300 from Magicshine presented me with several puzzles in the last few weeks. On several occasions, the light switched itself off while I was cycling or simply failed to detect the vehicles behind me. Turns out, the test device the manufacturer had provided me with was defective.
I’ve since received a new one and have taken it for a few spins. The finish is sturdy and high-quality. I like it. Other than that, it works according to the manufacturer’s specifications. However, the Seemee R300 fails to detect other fast-approaching bicycles, such as S-pedelecs. That’s frustrating and renders this model roughly useless, in my opinion.
As mentioned at the beginning, I often ride my gravel bike off busy main roads. But especially when I’m on side roads or forest paths, I want to be alerted if an e-bike is approaching quickly. After all, they’re a lot more present than cars when you’re cycling off the main roads.
Wahoo Trackr
Wahoo is the new kid on the radar block with its light called Trackr. At first glance, it seems a little on the cheap side in terms of hardware compared to the Seemee. The clunky mount in particular doesn’t spark much joy in me. However, I’ve only used the Trackr a few times so far.
According to the manufacturer, it detects approaching vehicles from a distance of up to 150 metres, adaptive lighting modes adjust to traffic conditions, while the brake light function increases luminosity when braking.
Verdict
Here’s my ranking of the radar rear lights:
Varia RTL515/516: the original from Garmin impressed me most with its sophisticated technology. The model Varia RCT715 with its built-in dashcam is significantly more expensive and it remains unclear whether or not the image material may be used in a potential court case.
Gardia R300 L from Bryton is great value for money above all.
Although the inner values of the new Trackr from Wahoo look great at first glance, its hardware still has room for improvement, if you ask me.
I placed the radar light from Magicshine last in this compact ranking. Although the finish of the Seemee R300 appears to be of high quality, the technology doesn’t seem to be fully developed yet.
Header image: Patrick Bardelli
Patrick Bardelli
Senior Editor
Patrick.Bardelli@digitecgalaxus.chFrom radio journalist to product tester and storyteller, jogger to gravel bike novice and fitness enthusiast with barbells and dumbbells. I'm excited to see where the journey'll take me next.
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