Garmin Varia RearVue 820 bike radar review

Patrick Bardelli

17.3.2026

Translation: Veronica Bielawski

Pictures: Patrick Bardelli

Smart rear bike lights with an integrated radar have been popular for several years. They provide visual and acoustic alerts to warn you about vehicles approaching from behind. Invented a good ten years ago, the bike radar is now entering the next gen with Garmin’s new Varia RearVue 820.

Over the years, plenty of manufacturers have joined the bike safety market, giving it the attention it deserves. Bryton, Wahoo, Magicshine, Lezyne and BBB Cycling are some of the most recent brands to have added versions of a bicycle radar and rear light to their range.

The goal of these gadgets is simple: to alert you to approaching vehicles. To work, you must pair the light/radar with a compatible bike computer, smartwatch or smartphone. Of course, you can go for a simple mirror mounted on your helmet or handlebars as a low-tech solution. But in some situations, you want the extra tech.

Here’s my previous overview of bike radars:

The world’s first radar system for bicycles was developed a good ten years ago by Garmin. Since then, the company has steadily refined the system, most recently launching the Varia RearVue 820.

Technical specs

• Dimensions: 98.9 × 25.9 × 43.2 mm
• Weight: 90 grammes
• Light modes: solid mode, peloton mode, night flash mode, day flash mode
• Custom light modes can be created in the Varia app for mobile
• Lumens: 25 in solid mode, 8 in peloton mode, 40 in night flash mode, 100 in day flash mode
• Water resistance: IPX7
• Battery life: 10 hours in solid mode, 15 hours in peloton mode, 10 hours in night flash mode, 24 hours in day flash mode, 30 hours in radar mode
• Visibility range: 2 kilometres
• Maximum vehicle detection range: 175 metres

What’s new

Put simply, compared with the earlier Varia RTL515/516, Garmin has equipped the new Varia RearVue 820 with a bit more of everything: better battery life, larger radar range, a wider field of view, stronger light output and greater visibility.

On top of that, the new Varia RearVue 820 can now identify three vehicle sizes. It shows you if what’s approaching from behind is a truck, car or another bike. For the most part, it works well. Every now and then, though, it struggles – for instance when trying to tell a truck from an SUV. The radar also shows when vehicles behind you change lanes. In addition, it has a brake light function, detecting when you slow down and displaying a unique flash pattern. No complaints there.

As mentioned, you can use the radar with a compatible bike computer, the Varia app on your smartphone or a compatible smartwatch. I paired it with my Edge 1040 Solar computer – mind you, its display feels a bit dated compared with newer models like the Edge 1050.

Still, it’s a real step forward that you now get more than just a little dot showing that something is approaching from behind. It makes a difference whether that «something» is a semi-truck or an S-pedelec.

I can’t speak on how the RearVue 820 works with a compatible Garmin smartwatch, as I didn’t test that function. According to Garmin, it’s currently only available on selected smartwatches as part of the company’s public beta programme.

Mount and installation

The Varia RearVue 820 comes with a USB-C cable (begone outdated micro-USB!) plus a seatpost mounting kit. With the different adapters included, the device should fit most road and gravel bike seatposts.

You can also get a seat rail mount for CHF 40. For a radar retailing at around CHF 300, it feels a bit audacious that Garmin wouldn’t just include this in the kit.

Which brings us to the price. The new radar is about twice as expensive as its predecessor and more expensive than any competing products. If I were to combine it with the Varia Vue front light and camera for just under 550 francs and the current Edge 1050 computer for 630 francs, I’d spend a total of nearly 1,500 francs. That’s a hefty sum.

Of course, pricing policy is a whole topic in itself, and everyone will have their own view on it. But for that amount of money, you can get a pretty decent gravel bike. But to each their own.

In a nutshell

Yes, but...

Let’s start with the good news: Garmin has replaced the outdated micro-USB port with a modern USB-C connection. High time. Compared with its predecessor, the Varia RearVue 820 offers more of everything – more battery, more lumens, more visibility and more range. The ability to distinguish vehicle size is another big plus, as are the brake light and lane-change functions. All that adds up to a fair bit of extra value.

Unfortunately, the same goes for the price, with Garmin hiking it up significantly. I’d recommend the following: if you already own the previous version or a radar from another brand, save your money. Sure, the extra functions are cool and genuinely useful. But the fact is you can do without them.

On the other hand, if you don’t yet own a radar, are planning to use it with a relatively new (Garmin) bike computer or your phone, and have the cash to spare, then go for it. The Varia RearVue 820 is a solid product.

Pro

• New features such as a brake light and lane-change function
• More battery life, lumens, visibility and range
• Finally, USB-C
• Vehicle size display

Contra

• Price
• Vehicle size display not always completely accurate

Bike lights

EUR381,30

Garmin Varia RearVue 820

25 lm

7

Patrick Bardelli

Senior Editor

Patrick.Bardelli@digitecgalaxus.ch

From radio journalist to product tester and storyteller, jogger to gravel bike novice and fitness enthusiast with barbells and dumbbells. I'm excited to see where the journey'll take me next.

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