review

Review: Garmin Varia RearVue 820

Andrew Ross

10 Feb 2026 — 6 min read

I’ve been using Garmin radars with my Edge cycling computer for a few years now. I find them to be an essential safety feature that, in my experience, are very reliable.

They help me to know what’s approaching from behind, how far away they are from me and how fast they are travelling. Notice the ‘help me’ - under no circumstances do I rely them instead of over a shoulder check. There are often times when a following car stays a steady, similar, speed to you and they drop off the radar. This was my main issue with the previous versions of the Varia radar. Despite this, having ridden with a radar for over two years I find not having a radar now rather unnerving when riding on busy roads!

The new Varia RearVue 820 attempts to solve the ‘steady’ vehicle problem as well as providing significantly more (too much?) information to help you monitor what is happening behind you. The new features in the RearVue 820 include:

Enhanced Radar: Detects vehicles up to 175 metres away with a wider field of view. Can identify vehicle size (small, medium, large) and lane changes.
Improved brightness: Brightest ever, visible up to 2 km away, with an automatic brake light that alerts others when you're slowing or stopping.
Better tracking and alerts: Tracks vehicles travelling at the same speed, provides visual/audible/haptic alerts via compatible devices.
Battery Life: Up to 24 hours in day flash mode.
More Light patterns: Four built in patterns plus custom patterns.

Unpacking

The RearVue 820 is packed very similar to all the other Garmin radars. Great to see this time that there is a lanyard included. 3 different mounts will help you to get a snug fit on most seat posts. There’s also a welcome, long overdue, USB C charger!

Installation

Installing on your seat post involves finding the best mount and then using the provided black elastic bands to attach it securely.

Connection to my Edge 1050 was picked up immediately in the sensors. Two connections are made - the first for the light and the second for the radar. I got a quick guide pop up when it connected.

I also connected the RearVue 820 to my phone via the Varia app. This allowed me to update the firmware.

Using the Varia app you can update the firmware, change the light settings and set the threat alerts.

Interestingly you can also connect then RearVue to your Garmin watch!

The Light

There are 6 options for the light (if you include off!):

Solid - The tail light is on at high brightness.
Peloton - The tail light is on at low brightness.
Night Flash - The tail light alternates between low and high brightness.
Day Flash - The tail light flashes on and off continuously.
Off - The tail light is off. (Note: The radar operates normally while the tail light is off.)
Your own option which you create in the Varia app.

You can also set in the app an option which, when the tail light is on and the radar detects a vehicle approaching behind you, the flashing pattern changes automatically to enhance your visibility.

According to the website the light is visible from up to 2km (1.24miles) away. I’m not personally convinced we need brighter and brighter lights (look at all the problems we have with bright headlights on cars) but you’re not going to be able miss this light. Make sure you turn it away from you when you turn it on - it’s very bright!

I walked 1.24miles from my house - no chance I could see the light based on the fact I was in the village - but I was amazed how far it was. I’m not convinced my eyes would even be able to pick up the light that far away even if it was in a perfect clear straight line!

An accelerometer inside the 820 also allows the light to brighten when braking. There is an option to turn this off in the Varia app if you don’t wish to use this feature.

The Radar

This is the improved feature that Garmin is selling the RearVue 820 on. There are three new ways to view approaching traffic on your Edge with the Varia RearVue 820. Tracking is available on all Edge devices but according to Garmin advanced vehicle tracking is only available on the Edge x40 and x50 devices.

Please check compatibility as what options you get is very dependent on which Garmin cycling computer you are using. As far as I’m aware you can’t use the new features on any non-Garmin device but it does still work as a standard radar.

You have three options (not including viewing on your phone).

Full screen:

Split Screen:

Traditional View:

All of these views work well. My favourite while I was testing was the traditional view although I did find that there was almost too much information to process at a quick glance down. The original overlay (with one line of traffic) works well, although it appears slightly more cluttered now - especially on a busy road with the different sized vehicles rather than dots. It is also noticeable that all the vehicles were on the right and I was in the centre - losing some of the limited screen estate to the left of me which very rarely had any traffic. The only spot where I noticed traffic on my left and right was when I was in a centre lane and there was a filter lane to my left.

On the short test rides I made the radar worked correctly identifying vehicles behind me. There were odd occasions where the size of the vehicle changed as it approached me - I assume that this was because the radar got clearer information as the vehicle got closer. Vehicles are identified as large or small and highlighted with a colour depending on the speed they are approaching you. I believe that it also show’s bikes as a different symbol although I wasn’t able to test this on my rides.

Again from the limited testing the radar appeared to track vehicles at the same speed as me - this was my one bug bear with the previous Garmin radar. Well done on solving this problem Garmin.

You can of course continue to use the Varia RearVue with your phone (or your watch) via the Varia app. This shows all the traffic information on your phone as well - useful if you have your phone mounted on your handlebars.

Battery Life

From the Garmin website:

Up to 10 hr. (Solid mode)

Up to 15 hr. (Peloton mode)

Up to 11 hr. (Night Flash mode)

Up to 24 hr. (Day Flash mode)

Up to 30 hr. with tail light off

I’ve not had time to test the battery life but Garmin have been reasonably accurate with the other items I have belonging to them.

Pros

Vehicles identified further away
Brake light function when slowing down
information on the size and speed of the vehicles behind you
Tracks vehicles travelling at the same speed as yourself.

Cons

Large amount of information which can take time to process whilst you are cycling.
One some screen layouts there is a lot of wasted space
Price
Ever increasing brightness of light

Is it worth it?

At £259.99 it’s not a cheap purchase but it appears to be the most accurate and feature rich radar out at the moment. Sometimes however as cyclists we don’t need all the extra features - we just need to cycle. Whilst I do rely on the radar now when riding I not sure that that I need all the extra information that the Varia RearVue 820 provides.

If you already have a radar I’d suggest you hold off buying at the moment. If you don’t own a radar and you have the money then this is definitely a great buy - it’s more reliable than previous Garmin radars, just don’t get too overloaded with all the information that it provides. If you don’t have the money previous Garmin radars still provide excellent value for money.