AI quick summary
- The Varia radar detects vehicles approaching from behind up to 140 m away, displaying them as dots on your head unit — how many, how fast, relative position. It works with Garmin, Wahoo, and Hammerhead head units
- The Varia tail light brightens and flashes faster as a car approaches — it's a rear radar AND a smart light. The combination is what makes it so effective: you know a car is there, AND the car sees you
- The Varia doesn't replace looking behind you — but it tells you WHEN to look and what to expect. For solo riding on roads with traffic, it transforms situational awareness
- All current Garmin head units (Edge 130+, 530+, 830, 1040, 1050) and many Wahoo and Hammerhead units support Varia radar display. The RTL516 (radar + light, micro-USB, ~$200) is the current model; the RTL515 (USB-C, slightly brighter light, ~$250) is the newest
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How it works
The Varia radar (model RTL516 or the newer RTL515) is a small, seatpost-mounted unit combining a rear-facing radar and a tail light. It emits a radar pulse that detects vehicles approaching from behind — up to 140 m away, tracking multiple vehicles simultaneously. The data is sent via ANT+ to your head unit, which displays a thin vertical 'radar strip' on the side of the screen: each approaching vehicle is a dot that moves up the strip as it gets closer. The radar also distinguishes between fast-approaching and slower-moving vehicles.
Connected to a compatible head unit (Garmin Edge, Wahoo ELEMNT, Hammerhead Karoo), the radar strip appears automatically — no setup beyond pairing. When a vehicle is detected, the tail light brightens and flashes faster, alerting the driver. The combination of radar AND smart light is what makes the Varia uniquely valuable — you know about the car AND the car sees you.
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What it changes
The Varia transforms road riding. On solo rides, you know whether you're about to be passed — and can move to the shoulder, move single file, or hold your line, knowing the car's speed and distance. On group rides, it's an extra set of eyes for the riders ahead — the Varia gives the group leader a count of approaching vehicles.
The Varia doesn't replace shoulder checks — but it tells you when to check, and what you'll see. Before a blind bend, you know there's a car coming. Before a narrow bridge, you know it's clear behind. The confidence it adds to riding on roads with traffic is the kind of thing that riders describe as 'once you use one, you won't ride without it.'
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Models and setup
Setup: mount the Varia on your seatpost with the included quarter-turn bracket, pair via ANT+ to your head unit (automatic on Garmin — just go to Sensors > Add Sensor), and you're done. The radar strip appears as a permanent vertical bar on the left (or right, configurable) side of the head unit screen. No subscription, no app required for core radar functionality.
Current Varia radar models. The RTL515 is the newest; the RTL516 is the value option.
| Model | Radar range | Light modes | Battery life | Charging | Price |
|---|---|---|---|---|---|
| RTL515 (newest) | 140 m | Day flash, night steady, peloton mode | 6–16 hr depending on mode | USB-C | ≈$250 |
| RTL516 (current, value) | 140 m | Day flash, night steady, peloton mode | 6–16 hr | Micro-USB | ≈$200 |
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