Bryton teased their Gardia rear radar back at Eurobike 2022 as a long awaited competitor against the Garmin Varia radar. Today, we finally have a production version for this review which not only competes with the Garmin Varia but also the relatively new Magicshine x Magene 508 radars. The Bryton Gardia R300L undercuts both radars with a competitive retail price of only $129.95 and a class-leading 190m detection range. The radar has a wide 220 degree field of view which allows you to spot cars around corners or in different lanes. Bryton has added a few modern features such as a brake sensor to detect when you’re slowing down and notify riders behind you as well as a USB-C charging port. The Gardia R300L can be paired with any GPS computer that supports radar displays or a stand-alone Bryton Gardia app to display oncoming vehicles and emit visual and audio notifications.

The Bryton Gardia R300L bike radar combines a modern design and bright LED with a highly competitive retail price.

Retail Price$129.95
Rating9.0 / 10
Measured Weight (in g)67 (radar) / 24 (seatpost mount)
Likes+ Competitive price that undercuts Garmin / Magicshine x Magene
+ Modern square design with focused and bright center LED
+ Slick stand-alone app to display vehicle information
Dislikes– Proprietary Bryton mount
– Current software has trouble identifying individual cars driving in clusters
– Brake sensor can reduce runtimes
Where to Buy (US) Bryton


The Bryton Garidia comes in a compact black cardboard box with glossy graphics and specs printed onto it. Inside the box you’ll find:

  • Gardia R300L radar
  • Seatpost mount + D-shape adapter + aero adapter
  • USB-C to USB-A charging cable
  • Quick start guide + safety information

Everything is well packed and it’s easy to quickly pair and start riding with the radar.


The Bryton Gardia R300L utilizes Bryton’s proprietary quarter-turn mount design. It’s essentially a Garmin mount but with thicker tabs. Although you can force it into a Garmin mount, we’ve found that it ends up bending the tabs over time which is why we don’t recommend it. Instead, Bryton includes a well designed seatpost mount that uses a standard rubber strap to attach to a seatpost. Right out of the box there are two additional rubber attachments: a flat rubber pad for d-shaped seatposts and a thicker pad for aero seatposts. Both attachments have cutouts that allow them to simply be inserted into the back of the mount. It’s an effective design that should work with nearly any bike setup and even has a built in angle offset to account for the seatpost angle. The only downside to the multi-piece approach is that you have to remember to keep track of the adapters.


Visually, the Bryton Gardia R300L doesn’t look significantly different from the Garmin Varia or Magicshine x Magene Seemee 508. The top third of the Gardia R300L is dedicated to the taillight while the bottom third is a flat surface for the radar. Dimensionally, the Gardia R300L is very close to other radars with a compact 40mm width, 97mm height and 20.9mm thickness. The big difference with the radar is that Bryton has utilized a square design, which in our opinion gives the Gardia R300L a more modern appearance. The surface of the radar has a matte plastic finish with rounded corners. Along the bottom edge you’ll find a horizontal cutout which hides the status LEDs to indicate battery status and Bluetooth connectivity. The taillight has a red lens with extended body for improved side visibility and a slight curved bottom edge which gives the radar a sleek look.

Bryton Gardia R300L Bike Radar Taillight Review - Illuminated Light
Bryton has utilized three LEDs in the tailight, a highly focused center light and then two smaller ones to illuminate the lens.

Even though Bryton isn’t a taillight company, they’ve done a great job designing the lens. In the center of the lens is a single LED with a focused reflector design to concentrate the light. This improves the long range visibility of the taillight and makes the light look a lot brighter than the 73 lumen maximum would suggest. There are two smaller LEDs at each side of the lens which help illuminate the lens and ensure the light is visible from side angles. It’s a similar feature to the Garmin Varia’s side LED markers but has a more integrated appearance here thanks to the larger lens housing.

Bryton Gardia R300L Bike Radar Taillight Review - Side View
Dimensionally, the Gardia R300L is very similar to the Magicshine / Magene 508 and Garmin Varia radar units and uses a simple quarter turn mount.

The Gardia R300L has a single button user interface with a wide raised button on the top of the radar. Bryton has kept the user interface simple and straightforward with a single-level menu with single presses to switch between modes and a long hold to turn the radar on and off. Unlike some products which use long holds to access configuration options, like the Trek Commuter Pro RT, additional features such as enabling or disabling the brake sensor can only be accessed via the companion app.  Underneath a large rubber cover below the molded-in Bryton mount is the USB-C charging port. It’s well designed and easy to open and close which is why the Gardia R300L achieves an impressive IPX7 water resistance rating.


Bryton has created a free standalone companion app called the Bryton Gardia app which can communicate with the radar. This is a great option for urban riders or those who prefer using their cellphones instead of dedicated GPS computers like the Bryton S800. We were pleasantly surprised with the app as it has a sleek design and doesn’t require logging in. You simply connect to the radar via the device manager option and can view the battery status as well as update the firmware. Once you have the radar synced you press “start riding” to display the radar view which shows a radar graphic and color coded cars as they approach. Within the app you can even switch the light output mode and enable or disable the brake sensor functionality. The app even offers audible or vibration notifications to ensure you’re aware of cars approaching. Aside from a few minor bugs such as the battery display not updating with beam mode and having to reconnect to the radar it’s a well designed app. If you’re familiar with Bryton then you know their main Bryton Active app has quite a few usability bugs which is why we are pleasantly surprised with the Gardia app.

Bryton Gardia R300L Bike Radar Taillight Review - Car Display
Radar information can be displayed on any compatible GPS computer or directly on Bryton’s Gardia app.


The Bryton Gardia R300L offers six different output modes which include two constant options, three flashing modes and a radar-only option. The two constant modes are high (20 lumen / 8 hours) and low (5 lumen / 12 hours). Flash modes include: night flash (12 lumen / 17 hours), day flash (73 lumen / 17 hours) and group ride (12 lumen / 10 hours). The night flash and day flash are quite similar with the day flash being brighter and better suited for daytime riding. Group ride mode is a more friendly pulse style mode better suited for riding in groups which alternates between a low / medium output mode instead of the more harsh on/off of the other flash modes.

We were quite impressed with the taillight performance as the focused center LED ensures vehicles see you from further distances away. The output of the radar is quite similar to the Bontrager Flare RT with the focused design. It’s a better taillight than the Magicshine / Magene 508 which have more of a distributed design that’s less visible from further distances. With the smaller side LEDs the entire lens of the taillight also becomes illuminated and helps with side visibility. We also tried the brake sensor mode which switches the light to a bright constant mode for a few seconds when braking is detected. The calibration is less sensitive than other lights we’ve used and can help alert riders behind you that you’re slowing down. However, the brake sensor isn’t perfect and results in false-positives that can reduce the runtimes significantly. That’s why we’d recommend leaving the brake sensor off via the app if you want more consistent run times.

The other aspect of the radar is the “warning mode” which activates each time a vehicle is detected. This switches the taillight from the current mode to a high-frequency flash mode to draw drivers attention to you. It’s quite effective as the pattern is erratic and bright. It’s similar to the warning feature on other radars and is something that cannot be disabled. In terms of runtimes, your results may vary from the claimed runtimes depending on how often the brake sensor and warning modes are triggered. Even with heavy traffic, the night and daytime flash offer more than enough runtime for doing all day rides which should be enough for most cyclists.


Even though Garmin has had the bike radar market to themselves for over half a decade, the Bryton performs quite well. The long range 190m detection range means the radar picks up cars before you can even hear them approaching. Bryton’s wide 220 degree visibility angle also means you pick up approaching cars even while you are riding on bike paths parallel to roads. The Gardia R300L also uses standard transmission protocols which ensures you get the color coded vehicle information (green = all clear, yellow = moderate speed and red = high speed) and multiple car display. With this early version of the software the only issue we found was that car clusters were not accurately detected. When multiple cars were driving close to each other, the radar would only show a single vehicle at a time until the lead vehicle passed. We suspect Bryton will address this issue within a software update or two. Otherwise, we didn’t experience false-negatives (cars being missed) and only had rare false-positives (phantom cars) that’s consistent with other radars on the market.


Overall, we found the Bryton Gardia R300L to be a well priced and designed radar. Bryton’s choice of a squared design and large taillight housing gives the Gardia R300L a modern appearance. The radar is nearly identical in dimensions to the Garmin Varia and Magicshine x Magene 508 designs with a slim elongated profile. We were impressed with the bright taillight as it offers a focused center LED for excellent far-range visibility on the road. Even the companion Gardia app which has a sleek UI design and is perfect for riders who want the radar functionality without a dedicated cycling GPS. The only negatives with the radar is that our early software version had issues detecting individual cars traveling in clusters and that the radar uses Bryton’s proprietary style mount. That said, if you’re looking for an affordable rear radar with well designed taillight the Bryton Gardia R300L is a highly anticipated option.

Disclaimer:  The product for this review was provided by Bryton. The views expressed on this website are solely those of the authors and are here to help people make an informed choice before a purchase. The authors or the blog itself does not get any monetary compensation from the product manufacturer or third-party websites/vendor links that are posted here.

2 Replies to “Bryton’s rear bike radar”

    1. Yes I believe it supports on-the-go charging, you have full control over the light even when it is plugged into a power source. The Gardia also works with any GPS that supports radar (Garmin / Bryton / Wahoo…) – it uses the same communication protocol as the Garmin Varia so you’ll get the same notifications.

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