Hot
- Onscreen visual alerts and distinction between approaching vehicle size (e.g., a bicycle, car, truck, truck w/trailer)
- Displays where vehicles are in relation to you (e.g., left, right, or directly behind)
- Tracks vehicles up to 175 meters (190+ yards) away with a wider field of view than previous models
- Vehicles traveling at the same speed no longer drop off the alert screen
- Brake light alerts riders and drivers that you are slowing or stopping
- Taillight visible up to 2 KM (1.24 miles) away
- Extended battery life compared to previous Garmin radar models
- Can mount the radar in either direction, with the light at the top or bottom
- Attaches to aero, round, or D-shape seat tubes (3 rubber shims included)
- Riders with compatible bike computers can pair to your Varia radar by adding it as a sensor
- Easy and quick pairing to the Varia app or Garmin device
- Use Garmin Express to install firmware updates
Not
- Not all features may work on older Garmin models
- Power button at the top (instead of the side), which made it difficult to reach with my saddlebag.
- Riders with short seat posts and/or saddlebags may not have enough room
- Pricey at $299.99
Price: $299.99
Battery Type: Rechargeable with micro USB-C cable
Battery Life: 10 hours solid, 15 hours peloton, 10 hours night flash, 24 hours day flash, and 30 hours radar-only
Seat Post Compatibility: Aero, round, and D-shaped
Visibility: 2 KM (1.24 miles)
Alerts: Visual and audible alerts for vehicles approaching up to 175 meters (190+ yards) away.
Connectivity: Bluetooth and ANT+
Dimensions: 3.9” x 1.0” x 1.7″ (98.9 x 25.9 x 43.2 mm)
Weight: 3.2 oz (90g)
Water Rating: IPX7 (suitable for splashes, rain, or snow showers)
Light Modes: Solid, peloton, night flash, day flash
Lumens: 25 solid, 8 peloton, 40 night flash, 100 day flash
Radar Beam Width: 60 degrees
Compatible Garmin Units: Garmin Edge cycling computer, Garmin smartwatch, or Varia smart device app. Not all functions work on all Garmin devices. View the full list of compatible devices here.
Options: Varia Seat Rail Mount Kit ($49.99)
Availability: Online and retail
How Obtained: Company sample
RBR Advertiser: No
A Game Changer – and I Don’t Use That Phrase Lightly
I’ve been riding with a rear radar ever since Garmin released its first Varia back in 2020. [Check out my past Varia RTL515/RVR315 and RTC715 reviews.] It doesn’t matter whether it’s on the road, gravel, or a trail; I always ride with a front headlight and rear radar. The radar keeps me constantly aware of what’s going on behind me without having to turn my head and look.
In February, Garmin released its newest radar, the Varia RearVue 820, and it’s a game changer. If you’re a Varia user, then you probably couldn’t imagine the radar getting any better. But Garmin proved us wrong. For those of you who have never used a radar, then it’s the perfect time to consider buying one.
Highlights of some of the new features making you safer on the bike include:
- a wider field of view to detect vehicles from over 190 yards away
- the ability to see a vehicle’s threat level, size, and side-to-side movement
- alert when a vehicle is following at the same speed as you
- Garmin’s brightest tail light for visibility up to 1.24 miles away
- longer battery life (24 hours in day flash mode) means more riding between charges
- a brake light with a unique flash pattern to warn drivers and riders when slowing or stopping
Knowing What’s Behind You
Previous versions of the Garmin Varia used dots to illustrate a vehicle or bicycle overtaking you. But the new 820 uses various sizes of rectangles to indicate what’s approaching from behind and uses a wider field of view to determine whether it’s on your left, right, or directly behind you.
The vehicle icons reflect the estimated size of the vehicle, as detected by the radar. As the vehicles approach, the icons move up the screen. You always know how many vehicles are approaching by the number of rectangles.
The radar continually reassesses and updates the icon to reflect the vehicle’s approximate size. One rectangle is a car, a larger rectangle is a truck, and two rectangles alert you to a vehicle pulling a trailer. The 820 can also discern a vehicle from a bicycle and displays it as a narrow rectangle.
Calculating the threat level based on vehicle size, speed, and lateral distance from your path, the radar displays them using the icons below.
When riding in a peloton or just one other rider, I’ll see a narrow rectangle on the screen. I see when the rider(s) drop back, so I know to slow down and let them catch my wheel again.
Also, unlike previous models, a vehicle or bicycle traveling at the same speed as I am will not disappear from the screen. Therefore, you are aware when a vehicle is waiting to pass, so you don’t accidentally pull out in front of it.
The Garmin Edge computer screen is customizable to display only the Varia radar data or combine it with additional data fields. I have my Garmin Edge 1040 Solar set up with 7 data fields, plus Varia data along the right-hand side of the head unit.
False Positives and Negatives
During my testing, I didn’t notice any false positives or negatives except on one particular ride. A friend who also uses the Garmin Varia 820 was drafting behind me. It was a very windy day, and she had to shift slightly left or right to stay in the draft. My radar alerts went off constantly as she adjusted her position. It was so annoying for both of us that I had her ride in front of me for a while to get some peace and quiet. We tried to figure out why this was happening, but couldn’t reach a valid conclusion.
A few days later, we went for another ride. However, on this occasion and subsequent rides, the Varia 820 performed flawlessly. She was able to draft behind me without setting off constant alerts.
When road riding, I still use a rearview mirror attached to my sunglasses. I use it to confirm the rear radar alerts. Now that the technology has gotten so much better, I’m considering eliminating the mirror.
What’s in the Box
The Varia 820 comes with three rubber shims to accommodate a variety of seat posts, including round, aero, and D-shaped. When mounting the unit, use the correct shims to ensure the radar is perpendicular to the ground. When mounting the radar, it can go either light down or up. For tighter configurations, you may want to have the light up so the power button is at the bottom.
Unfortunately, due to the saddlebag on my road bike, there’s very little room to mount the radar. Also, with the quarter-turn mount, the radar hits the seat stays when mounting or removing. I don’t experience this problem with the Varia RCT715 radar, which uses a straight-on mount.
Share With Others in the Peloton
If your riding buddies don’t have a rear radar, they can leverage yours. Have them add your Varia radar by adding it as a sensor. Remember, the audio and visual alerts are triggered only by what is behind you, since the radar is on your bike. Your buddy should ride with a taillight for visibility, even if they are using your radar.
I tested sharing the radar with a rider who was using a Garmin Edge 1030. Their visuals were dots, not the various-sized rectangles I see on my Edge 1040 Plus Solar. But having some alerts is better than nothing.
Comparing the Sizes of the Various Varia Models
I use all three Varia rear radars on my various bikes. The RCT715 with a rear camera was always on my road bike until I received the 820. The RTL515 was exclusively on my gravel bikes, but has since been replaced by the 820.
The RTL515 and 820 weights are comparable (72g vs. 87g) and use a quarter-turn mount, similar to the Garmin head units. They also both have the power button on the top. However, the 820 can be mounted “upside down,” with the power button at the bottom and the light at the top.
Why would you want the power button at the bottom? If there’s not enough room between the bottom of the saddlebag and the top of the radar. On rough roads, I’ve had the saddlebag hit the power button, turning off the radar mid-ride.
One other nice upgrade from the RTL515 is that the 820 uses USB-C, which means faster charging times and one less unique cable to bring when traveling.
As for the RCT715 model, it is bigger and heavier (147g vs. 87g) than the 820. It also uses a straight mount that locks the radar securely in place. The 820 comes with a tether to secure it to the saddle rails for added peace of mind. However, if you have a saddlebag, it’s difficult to find something to secure the tether to. Another feature difference to note is that the power button on the RCT715 is on the side, making it easier to access.
The location of the power button for turning the unit on or off becomes moot if you create a light network. Therefore, when you turn on the Garmin Edge, the lights automatically turn on and vice versa. But it doesn’t solve the problem if the saddlebag hits the power button on a bumpy road or gravel trail.
Bottom Line
If you don’t have a rear radar, it’s time to consider investing in one. At $299, the Garmin Varia RearVue 820 is pricey, but it sets the bar for all other radars. For me, its features are worth every penny. Can you really put a price tag on safety?
After reading this review, you still aren’t sure if you want a radar. Just find a buddy who has one and add it as a sensor on your bike GPS. Or ask your LBS if you can borrow a demo model. You’ll get a sense of what it’s like to be aware of what’s going on behind you and feel safer riding.
When heading out for a ride, two pieces of bike gear are non-negotiable for me: a quality helmet and a rear radar.
Sheri Rosenbaum regularly contributes articles and reviews products for RBR. She’s an avid recreational roadie who lives in the Chicago area and a major advocate for women’s cycling, serving on the board of directors and volunteering with the Dare2tri Paratriathlon Club. Click to read Sheri’s full bio or visit her web site sunflowersandpedals.com.
I just got one and it’s going back. No matter what I did I couldn’t get it to connect. I’m tired of being Garmin’s beta tester.