Radar…for your bike? It sure sounded like a gimmick designed to separate cyclists from their money, but at the insistence of some riding buddies who already owned one, I ordered a Garmin Varia Radar. I realized my assumption was off base and this little device would totally change the way I biked on the road.

What Is the Garmin Varia Radar?

The Garmin Varia is a rear-facing radar that attaches to the seatpost of your bike and alerts you about approaching traffic.

The Varia product line currently includes a few different models, including the Varia RCT715 which includes a rearview camera and taillight, the Varia RTL515 which includes a taillight, and the standalone radar Varia RVR315. I’m riding with the RTL515, but the radar functions work the same on all three devices. I’m looking forward to getting my hands on an RCT715 and testing out the rear-facing camera. Since a good taillight is essential for safe riding, I would only recommend the RVR315 as a stand-alone radar for riders that have integrated taillights or other lights already equipped.

Radar Functions

The radar can detect vehicles from 140 meters away, although this does rely on a clear line-of-sight from radar to vehicle. Alerts are displayed on a compatible device, including a Garmin Edge bike computer, Garmin wearable smartwatch, or a compatible smartphone with the Garmin Varia smartphone app. An audible alert is played on the device, and a live tracker of the vehicle shows up on the screen as well. Watches also provide vibration alerts along with a visual alert. Once the coast is clear, a green dot flashes on the display device.

Varia units broadcast on both Bluetooth BLE and ANT+ protocols, and are compatible with head units from other brands including Wahoo and Karoo, as well as third-party apps including RideWithGPS. GPS head units and smartphones can also control the camera setting of the RTL715, change light modes for the RTL515, and point toward oncoming traffic.

Multiple adapters are included for different-shaped seatposts, including d-shaped and rounded options. When mounting, it’s important to make sure the radar clears the rear tire so it can see oncoming cars and is mounted in the proper orientation and angle (there are helpful pictures in the instruction manual). Aftermarket mounts are also available from Garmin as well as third-party brands which allow riders with short seatposts, aero posts, or rear racks to mount their Varia with a clear view of oncoming traffic.

Taillight Features

The taillight can be seen from up to a mile away, and when paired with a compatible device, automatically changes between day flash mode and night solid mode. For its size, the light is impressively bright in both day and night modes.

More than once I’ve gotten dropped on a group ride and spent the next few miles tormented by a sea of twinkling lights as the pack rides away. The Varia also has “Peloton Mode” for group rides, which dims the intensity of the light until a vehicle approaches.

Battery Life

The Varia has more than enough battery life for 95% of my rides. Based on my experience, I think Garmin’s advertised time of 6 hours of battery life in day mode is an underestimate. On centuries and longer rides, I do shut it off during stops to conserve battery but haven’t had any issues with mid-ride shutdowns when starting with a full charge. The RTL515 has to shut down when charging, unlike Garmin head units which can charge while turned on. I hope this is addressed with newer models and the Varia gains the ability to charge in place as this would be an improvement for endurance events and overnight adventures.

On the Road

So how does it work on the road? Overall, I am incredibly impressed with the performance of the Varia. After years of riding, I thought I had a finely-tuned ear for approaching cars, but the Varia consistently detects vehicles before I hear them. It also displays multiple indicators for multiple vehicles, or for larger vehicles like trucks and tractor-trailers. It’s easy to check for an all-clear before pulling back out into the lane, and I no longer find myself surprised by a truck pulling a trailer or camper.

Most of my road riding is on quiet country roads in Upstate New York and Vermont. We’ve got beautiful rolling hills, but the pavement suffers from long winters and is usually cracked and potholed. While the roads are mostly quiet, when cars do pass, they are often going 40-60 miles per hour. Having advance warning allows me to use more of the lane most of the time before moving over for safety.

Why I Love the Garmin Varia Radar

• Versatility: I use the Varia on my road, gravel, and commuter bikes. It uses a standard mount and is easy to swap between bikes. It also automatically changes from day flash to night mode, which gives me one less thing to think about during winter commutes or when a road ride extends past dusk.
• Social Rides: I feel much safer riding two wide and chatting, and feel like we have plenty of time to merge to a single file when a car approaches.
• Workouts: Even if I’m totally spent at the end of a hard effort, my Varia lets me know traffic is coming so I can move over. This makes me more comfortable doing hard workouts on the road instead of the trainer.
• High-Speed Descending: One of my favorite things to do on a road bike is push down a twisting, high-speed descent. Between the wind noise and curves, it’s tough to tell when a car is coming. The Varia lets me know if I can cut the apex of a turn or should stick to the shoulder.

What Could Be Improved

While it’s an amazing piece of technology, the Varia is not perfect. Here are three things that I don’t love about it:

• Shutdown Difficulties: The rubber bands that hold the Varia onto the seatpost can stretch when the power button is pressed, resulting in the button not being clicked and the device staying on. This tends to happen when I’m cracked at the end of a big ride and not paying much attention. The standby indicator light blinks infrequently, and I’ve sometimes only realized it was still on when I found it dead the next time I headed out to ride.
• The Shadow Effect: On twisting roads, the Varia can sound a premature “all clear” when a vehicle is hidden behind a curve. Once the road straightens out, it detects the vehicle again, but riders should use common sense in these situations and confirm the all-clear with a look over the shoulder.
• Taking it for Granted: Sometimes I ride my mountain bike on the road between trailheads or for a recovery ride. I forget I don’t have the Varia watching my back and find myself drifting toward the middle of the lane!

Overall, the Garmin Varia Radar is a rare piece of cycling technology that exceeds the hype around it.** **It’s my favorite accessory to recommend to customers, as well as friends and family. Sharing the road with drivers is a constant challenge for cyclists, and riding with a Garmin Varia is a big step toward making road riding safer and more fun.

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