The Garmin Varia RearVue 820
See Behind You. Ride With Confidence.
The Light That Changed Cycling
The original Garmin Varia radar tail light changed the way cyclists think about riding in traffic. For the first time, you didn't have to guess what was coming up behind you - you knew. The Varia became the most popular cycling accessory Garmin has ever made, and for good reason: once you ride with rear-facing radar, you never want to ride without it.
The RearVue 820 is the first true successor to that legacy. Not a minor refresh - a ground-up upgrade across every specification that matters. Brighter. Smarter. Wider detection. Longer battery. And finally, USB-C.
175 Meters of Awareness
The RearVue 820's radar detects vehicles up to 175 meters behind you - 35 meters farther than its predecessor - with a 60-degree field of view that picks up movement several lanes across, not just directly behind. You get visual and audible alerts on your Garmin Edge, compatible watch, or the Varia smartphone app, so you know what's coming before you hear it.
That kind of lead time changes how you ride. You're calmer, more confident, and more aware - especially on open roads where you can't see around the next bend.
Brighter. Smarter. Safer.
At 100 lumens in Day Flash mode, the RearVue 820 is 58% brighter than the RTL515 it replaces - visible from over 1.2 miles away. But raw brightness is only part of the story. The 820 also functions as an intelligent brake light, automatically detecting when you're slowing or stopping and alerting drivers behind you with a distinct flashing pattern.
You don't press a button. You don't think about it. You just ride, and the light responds to what you're doing.
Engineered for the Real World
The RearVue 820 is the kind of product where every detail reflects thousands of hours on the road. The mount system accommodates round, aero, and D-shaped seatposts. The USB-C port charges fast and uses the cable you already carry. The 90-gram body tucks behind your saddle and disappears.
It's designed to be the one thing you never forget to charge - because it's the one thing you never want to ride without.
Advanced Vehicle Tracking
The RearVue 820 doesn't just tell you a car is behind you. It tells you how big it is, how fast it's closing, whether it's changing lanes, and how much of a threat it represents. Small, medium, and large vehicle classifications appear on your Edge screen in real time - so you know the difference between a passing sedan and an approaching truck before you ever turn your head.
The Technology Inside
As vehicles approach from behind, the RearVue 820 categorizes them by threat level based on speed, trajectory, and lateral movement. Higher-threat vehicles get more urgent visual alerts on your Edge or watch - the information you need, prioritized the way you need it.
An accelerometer detects when you're decelerating and triggers a distinct rapid-flash pattern that signals braking to drivers behind you. No button press, no delay - just an automatic safety response when it matters most.
Not every threat is a fast-approaching vehicle. The 820 also monitors vehicles traveling at your speed or waiting to pass - the situations where a car lingers in your blind spot longer than you'd like. You'll see them on your screen until they clear.
The Varia app lets you design your own flash patterns - controlling brightness level, flash duration, and rhythm to match the conditions of your ride. Build a high-visibility pattern for busy commutes or a subtle pulse for group rides.
New for the 820: the radar classifies approaching vehicles as small, medium, or large. That truck closing behind you on a narrow road? You'll know it's a truck - not a car - with enough time to position yourself accordingly.
24 Hours of Protection
Battery anxiety has no place on a long ride. The RearVue 820 delivers up to 24 hours in Day Flash mode, 15 hours in Peloton mode, and 30 hours in radar-only mode - enough for the longest gran fondos, multi-day tours, or a full week of commuting without touching the charger. And when it is time to charge, USB-C means you're using the same cable as your phone, your Edge, and everything else in your kit bag.
Four Modes for Every Ride
Day Flash at 100 lumens for maximum daytime visibility. Night Flash at 40 lumens for after-dark rides without blinding the group behind you. Solid at 25 lumens for steady visibility. Peloton at 8 lumens when you're riding in a pack and need radar without the full light show. Each mode keeps the radar active, and you can switch between them with a single press - or set your Edge to manage the light automatically based on ambient conditions.
Works With What You Ride
The RearVue 820 connects via ANT+ and Bluetooth simultaneously - pairing with Garmin Edge computers for the full suite of advanced features, with Garmin watches for on-wrist alerts, and with third-party computers from Wahoo, Hammerhead, and Stages for standard radar notifications. The Varia smartphone app turns your phone into a radar display if you ride without a head unit. One device, every setup.
Mounts in Seconds. Fits Every Bike.
The included mount kit covers round, aero, and D-shaped seatposts with three interchangeable adapters and two sizes of double-wide bands. A quarter-turn mechanism locks the unit in place and releases it just as quickly for charging. At 90 grams and 98.9mm tall, the RearVue 820 tucks behind your saddle without adding visual clutter or meaningful weight - and it's IPX7 rated, so rain is never a reason to leave it at home.
USB-C Charging
The RearVue 820 finally moves to USB-C - the same port on your phone, your Edge, and your laptop. One cable in the kit bag, everything charges. No more hunting for that one Micro-USB cable you keep losing.
Peloton Mode
An 8-lumen steady glow keeps you visible without blinding riders behind you in a group. Radar stays fully active, so you still get vehicle alerts - but the light output respects the etiquette of the pack.
IPX7 Water Resistance
Rated for submersion at 1 meter for 30 minutes. Translation: rain, puddles, road spray, hose-downs after muddy rides - none of it matters. The RearVue 820 keeps working when the weather doesn't.
Varia Smartphone App
No Garmin head unit? No problem. The free Varia app for iOS and Android turns your phone into a full radar display - showing approaching vehicles, threat levels, and light controls right on your screen.
Specifications
The RearVue 820 is a single-SKU product - one size, one color, everything you need in the box. Here's what you're getting.
| Spec | Detail |
|---|---|
| Dimensions | 3.9 x 1.0 x 1.7 in (98.9 x 25.9 x 43.2 mm) |
| Weight | 3.2 oz (90 g) |
| Water Rating | IPX7 |
| Radar Detection Range | 175 m (190+ yards) |
| Radar Beam Width | 60° |
| Visibility Distance | 1.24 mi (2 km) |
| Lumens | 100 (Day Flash) | 40 (Night Flash) | 25 (Solid) | 8 (Peloton) |
| Battery Life | 24 hr (Day Flash) | 10 hr (Night Flash) | 10 hr (Solid) | 15 hr (Peloton) | 30 hr (Radar-Only) |
| Light Modes | Day Flash, Night Flash, Solid, Peloton |
| Connectivity | ANT+ and Bluetooth (simultaneous) |
| Charging | USB-C |
| Vehicle Size Classification | Yes (small, medium, large) |
| Vehicle Threat Classification | Speed-, size-, and lateral range-based |
| Brake Light | Yes (automatic) |
| Viewing Angle | 220° |
| Varia App | Yes (iOS and Android) |
| Custom Light Patterns | Yes (via Varia app) |
| In the Box | Varia RearVue 820, mounting kit, USB-C charging cable, documentation |
