Garmin Varia Rearview 820

A rear radar's job is to tell you something is coming before you hear it, and how much detail it gives you about that something is where these units separate. Garmin's Varia RearVue 820 detects vehicles up to 175 meters behind you and pushes audible and visual alerts to an Edge cycling computer, a compatible Garmin smartwatch, or the Varia app on your phone. The radar beam spans 60°, wide enough to register traffic moving laterally several lanes over, and the system sorts what it sees into small, medium, and large vehicles while assigning a threat level based on speed, size, and how far to the side the vehicle sits.

The tail light side runs 4 preset modes: 100 lumens in day flash, 40 in night flash, 25 solid, and 8 in peloton mode for group rides where you don't want to cook the eyes of the rider on your wheel. Custom patterns can be built in the Varia app. A brake light function throws a distinct flash pattern when the radar senses you slowing or stopping. Runtimes land at 24 hours in day flash, 15 hours peloton, 10 hours solid or night flash, and 30 hours with the light switched off and the radar running alone.

Sort this out before you buy: the advanced vehicle tracking, meaning size classification and left-right lane movement, runs over a secure Bluetooth channel that only recent Edge computers support, specifically the x40 and x50 series. Wahoo, Hammerhead, Bryton, and older Edge units pair the RearVue 820 over ANT+ and get the standard radar display, including same-speed tracking of vehicles sitting behind you, but not the vehicle size icons or lane positioning. If your head unit is a few generations back, you're buying detection range and runtime, not the new display features.... Read More