Garmin Varia RVR315 Rear Radar Cycling Light for Road Safety

The Garmin Varia RVR315 is a rear cycling radar and light combined into a single, compact unit — and it's one of the most genuinely useful safety upgrades you can add to any road or gravel bike. The RVR315 detects approaching vehicles from up to 140 metres behind you and alerts you via a paired Garmin Edge computer, compatible head unit, or the Varia app on your smartphone, giving you advance warning of traffic long before you'd hear or see it yourself.

The integrated rear light is no afterthought: it operates in solid and flashing modes and automatically adjusts brightness based on ambient light conditions, ensuring you're always visible to drivers without you having to think about it. The aerodynamic, low-profile design adds minimal drag and weight to your seatpost, and installation takes seconds with the included mount. Battery life is strong enough for extended rides, and the unit charges via USB.

Where the Varia RVR315 really earns its place is in the ecosystem integration. Paired with a Garmin Edge computer, approaching vehicles appear as alerts on your screen — a yellow alert for a vehicle detected in the distance, turning red as it closes in. This gives you time to move to a safer road position, check your mirror, or simply ride with greater awareness and confidence. It's particularly valuable on fast descents, narrow lanes, and any road where you can't easily look behind you. Browse the full Garmin range or explore our complete lights collection and rear lights for complementary products.

The RVR315 is the radar-only variant in the Varia range — if you'd prefer a model with a more powerful integrated light, explore the wider Varia lineup. For most road and gravel riders, the RVR315 strikes an excellent balance of radar capability, light output, and compact form factor.

What It's Good For

• Detecting approaching vehicles up to 140m behind you and alerting you via a paired Garmin Edge or the Varia app
• Adaptive rear light that automatically adjusts brightness to ambient conditions
• Road and gravel riding where rear traffic awareness significantly improves safety
• Seamless integration with Garmin Edge computers for on-screen vehicle alerts
• Fast descents, narrow lanes, and any situation where looking behind is difficult or dangerous
• Compact, aerodynamic seatpost mount with quick installation

What It's NOT Good For

• Off-road MTB use where rear vehicle traffic is not a concern
• Riders wanting a high-powered rear light as their primary visibility tool — the RVR315's light is designed to complement the radar function; other Varia models offer more powerful light output
• Use without a paired device — radar alerts require a compatible Garmin Edge computer, head unit, or the Varia smartphone app to be displayed
• Replacing attentive riding and road awareness — the Varia is a safety aid, not a substitute for good road craft

Frequently Asked Questions

How does the radar work?
The Varia RVR315 uses radar technology to detect vehicles approaching from behind at up to 140 metres. When a vehicle is detected, an alert is sent to your paired Garmin Edge computer or the Varia smartphone app — a yellow indicator appears as the vehicle is detected, turning red as it closes in. This gives you several seconds of advance warning to adjust your road position.

Does it work without a Garmin Edge computer?
Yes — the Varia RVR315 can be paired with the free Varia app on a compatible smartphone to display radar alerts, so you don't need a Garmin Edge to benefit from the radar functionality. However, pairing with a Garmin Edge computer gives the most seamless, glanceable experience.

Which Garmin Edge computers are compatible?
The Varia RVR315 is compatible with a wide range of Garmin Edge computers including the Edge 540, Edge 840, Edge 850, Edge 1040, and Edge 1050. Check Garmin's compatibility list for the full range of supported devices.

How long does the battery last?
Battery life varies depending on the light mode used. In radar-only mode the battery lasts longer; combined radar and light modes reduce runtime. The unit charges via USB and is straightforward to top up between rides.