Ride with confidence on busy roads with the Garmin Varia RearVue 820, the most advanced rear-facing radar and tail light Garmin has ever built. Designed to dramatically improve rider awareness and visibility, the RearVue 820 detects approaching vehicles from behind and delivers clear visual, audible and vibration alerts to compatible Garmin Edge cycling computers, smartwatches or the Varia smartphone app.

Using Garmin’s new high-precision radar technology, the RearVue 820 doesn’t just detect cars — it tracks vehicle speed, lateral movement and size, and assigns a real-time threat level as traffic approaches. Riders are alerted sooner and more reliably, even when vehicles are travelling at the same speed or waiting to pass.

Visibility is equally impressive. The RearVue 820 is Garmin’s brightest tail light to date, visible from up to 2 km away in daylight. An integrated brake light automatically flashes when you slow or stop, clearly signalling your intentions to motorists and other riders. Multiple light modes are available, including day flash, night flash, solid and peloton modes, with full customisation through the Varia app.

With up to 24 hours of battery life in day flash mode and up to 30 hours in radar-only mode, the RearVue 820 is built for long rides, commuting and endurance training. A sleek, compact design, USB-C charging and a secure new seat post mount make it easy to fit to almost any road or gravel bike.

Whether you’re commuting through traffic or training on open roads, the Varia RearVue 820 delivers a new level of awareness, visibility and peace of mind.

Key Features & Benefits

• Advanced rear-facing radar detects vehicles up to 175 m away

• Vehicle size detection (small, medium, large) displayed on compatible devices

• Threat level alerts based on speed, position and movement

• Same-speed tracking alerts you to vehicles following behind

• Extra-wide field of view tracks traffic across multiple lanes

• Bright 100-lumen day flash visible up to 2 km away

• Automatic brake light activates when slowing or stopping

• Customisable light modes via the Varia mobile app

• Up to 30 hours battery life in radar-only mode

• USB-C charging for convenience and durability

• ANT+® and Bluetooth® connectivity

• IPX7 water rating for all-weather riding

Technical Specifications

General

• Dimensions: 98.9 × 25.9 × 43.2 mm

• Weight: 90 g

• Water Rating: IPX7

Light Output & Modes

• Light Modes: Solid, Peloton, Night Flash, Day Flash

• Lumens:

  • Solid: 25 lm

  • Peloton: 8 lm

  • Night Flash: 40 lm

  • Day Flash: 100 lm

• Custom Light Modes: Yes (via Varia app)

• Visibility Distance: Up to 2 km (1.24 miles)

Battery Life

• Solid: Up to 10 hours

• Peloton: Up to 15 hours

• Night Flash: Up to 10 hours

• Day Flash: Up to 24 hours

• Radar-Only Mode: Up to 30 hours

Radar Performance

• Maximum Detection Range: 175 m

• Viewing Angle: 220°

• Radar Beam Width: 60°

• Vehicle Tracking:

  • Lateral vehicle positioning

  • Vehicle size classification

  • Vehicle threat classification (speed, size & position based)

• Same-Speed Vehicle Tracking: Yes

Connectivity

• ANT+®: Radar & bike light

• Bluetooth® (BLE): Radar & bike light

• Compatible With: Garmin Edge cycling computers, compatible Garmin smartwatches and Varia mobile app

What’s in the Box

• Garmin Varia RearVue 820 radar tail light

• Seat post mounting kit

• USB-C charging cable

• Documentation