The Garmin Varia RearVue 820 is the latest evolution in cycling safety technology, marking a significant leap forward from the industry-standard RTL515. While previous models were excellent at "detecting" objects, the RearVue 820 is built for advanced vehicle tracking. It doesn't just tell you a car is behind you; it provides critical data on the size of the vehicle (differentiating between a motorcycle, a passenger car, or a large truck/bus) and its lateral position, alerting you if a vehicle is changing lanes as it approaches.
With an expanded detection range of 175 metres and a wider 60-degree radar beam, the 820 offers a much broader field of view, making it more effective at tracking traffic across multiple lanes or on winding roads. The addition of a dedicated brake-light function also ensures that those following you—whether they are motorists or other riders in your bunch—are immediately alerted when you begin to decelerate.
Advanced Vehicle Tracking: Displays the approximate size of the approaching vehicle and its lane position on compatible Edge computers or the Varia app.
175m Detection Range: An increased range (up from 140m on the RTL515) gives you more time to react and prepare for high-speed overtakes.
Integrated Brake Light: Automatically detects deceleration and triggers a unique, high-intensity flash pattern to signal to those behind that you are slowing or stopping.
Expanded Connectivity: Now features Secure Bluetooth® pairing and is fully compatible with ANT+ radar and light standards, as well as the Varia smartphone app.
USB-C Charging: Finally moves away from Micro-USB, offering a more durable, faster-charging, and modern connection port.
Same-Speed Tracking: Alerts you to vehicles or even other cyclists that are pacing behind you at the same speed, ensuring you aren't surprised when they eventually pull out to pass.
| Feature | Specification |
| Detection Range | Up to 175 Metres |
| Viewing Angle | 220 Degrees |
| Radar Beam Width | 60 Degrees |
| Max Battery Life | 24 hrs (Day Flash) / 30 hrs (Radar Only) |
| Luminous Flux | 100 Lumens (Day Flash) |
| Weight | 90g |
| Water Rating | IPX7 |
The High-Speed Commuter: If you ride on multi-lane arterial roads, the ability to see lane-change alerts on your head unit provides a massive boost in situational awareness.
Endurance & Tour Riders: With up to 30 hours of battery life in radar-only mode, this unit can easily cover a full weekend of riding on a single charge.
Group Ride Enthusiasts: The Peloton Mode (8 lumens) and the Brake Light make this the ultimate "friendly" radar for bunch rides, providing safety without blinding your mates.
Minimalist Safety: If you just want basic "car behind" alerts and don't need vehicle sizing or lane tracking, the older Varia RTL515 remains a lighter and more affordable entry point.
Weight Obsessives: At 90g, it is slightly heavier than the 71g RTL515. For ultra-light climbing builds, some riders may prefer the screen-only Varia RVR315 which has no light.
The RearVue 820 features a new mounting interface that is more robust than the older quarter-turn systems. To get the most accurate "lane tracking" data, ensure the unit is mounted perfectly vertical and at least 70cm-100cm from the ground. If you find the alerts are "chirping" too much in heavy CBD traffic, you can use the Varia app to customize the alert tones or switch to "vibration-only" mode on your Garmin watch. Finally, remember that while this unit is USB-C, it is always best to use the included cable to ensure a perfectly weather-sealed connection during charging!
