{"id":1760151,"date":"2026-02-10T01:50:15","date_gmt":"2026-02-09T22:50:15","guid":{"rendered":"https:\/\/analyse.optim.biz\/?p=1760151"},"modified":"2026-02-10T01:50:15","modified_gmt":"2026-02-09T22:50:15","slug":"garmin-rearvue-820-first-look-the-worlds-first-drafting-sensor","status":"publish","type":"post","link":"https:\/\/analyse.optim.biz\/?p=1760151","title":{"rendered":"Garmin RearVue 820 First Look: The World\u2019s First Drafting Sensor"},"content":{"rendered":"
Last week, Garmin introduced the RearVue 820 as a long-awaited update to the brand\u2019s Garmin Varia RTL515. Now that I\u2019ve had a chance to test it, I\u2019m here to say it\u2019s brilliant, and it\u2019s got a feature nothing else on the market can match. I know I\u2019m not supposed to give that away in the first few sentences, but there\u2019s not much point in delaying the obvious. There is, however, one big drawback that I\u2019ll get to in a bit.<\/p>\n<\/figure>\n
The reason it\u2019s so easy to make the assessment that the RearVue 820 is good is because it\u2019s mostly a known quantity. Garmin bought radar technology by acquiring a company called iKubu in early 2015 and in August of that year the first radar units hit the market.<\/p>\n
At that point the idea of radar on the back of your bike was novel. Reviewers had to look at not only if it worked but also explain the basic concept. In 2018, when the RTL510 hit the market, the technology was already quite mature and the now familiar silhouette of a Garmin Varia tail light was introduced.<\/p>\n<\/figure>\n
By the time the RTL515 came to market in 2020 the idea was established. That release was a collection of quality of life updates such as an available connection via Bluetooth, extended 16-hour battery life, Peloton mode, and more mounting options, but the core functionality didn\u2019t see any updates. Even back then you didn\u2019t have to explain what the concept was and talking about if it fundamentally worked or not was more about checking it off the list rather than actually finding problems.<\/p>\n
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Then the design froze in time. Nothing changed about the RTL515 between 2020 and 2026. If there was any doubt left, the unit was firmly ensconced as the market leader in terms of vehicle detection. A variety of competitors came to market competing on price or other features, but the Garmin radar detection was the gold standard. Every other review had to establish that vehicle detection was as good then you could look beyond that. As the years kept rolling it was increasingly hard to recommend the RTL515 but only because it was a dinosaur with an outdated charging port and old battery technology.<\/p>\n
Now we are finally looking at a real update to that RTL515 and if you use that unit as a gold standard everything is the same or better. Nothing has been taken away but features have been added. The battery life on the older unit was among the best, even in 2025, and the new unit is now the best again. The new unit is brighter and the new mounting is marginally better but still compatible with third party mounts. And that detection that was already the best\u2014only matched by Trek, Wahoo, and Lezyne\u2014is now the same or better.<\/p>\n<\/figure>\n
What I like: same speed tracking is the real hero<\/h2>\n
Most eyes are going to be on features like lane detection and vehicle size. There\u2019s also going to be plenty of ink spilled for the hardware upgrades that had to happen in 2026. I\u2019ll cover both of those but neither of those is the real star here. The game changing feature that no other radar unit can match is same speed vehicle tracking.<\/p>\n
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Honestly speaking, this wasn\u2019t a feature I even saw coming. I would never have guessed this was even a possibility because all radar units suffer from the same problem. Cars vanish from detection when they match your speed, and it\u2019s not so much a \u201cbug\u201d as a \u201cfeature\u201d of the way radar works.<\/p>\n
These units work by measuring the frequency shift of a bouncing signal. When a car matches your pace, that shift drops to zero. To the sensor, the vehicle suddenly has the same relative profile as a tree, causing the software to filter it out as stationary background noise.<\/p>\n
Garmin fixed this and it didn\u2019t take magic to do it, just clever processing. My guess is that the RearVue 820 uses signal persistence. Once the radar identifies a high-intensity target, the software maintains a memory of that object even when the relative speed difference is zero. The result is that a car that\u2019s behind you stays as an active alert until passing or falling out of the detection range.<\/p>\nYou\u2019ll need to choose the large version want lane information but it\u2019s barely bigger. <\/span><\/figcaption><\/figure>\n
This has another effect though. Something no one else is talking about, but is absolutely brilliant. Radar technology was always able to detect other bikes but if they matched your speed they\u2019d disappear just like a car. Same speed tracking turns the RearVue 820 into the world\u2019s first drafting sensor. The unit doesn\u2019t just see cars. The RearVue 820 sees your riding partner and it tells you not only whether you are dropping them or not but also how close they are and how directly they are behind you.<\/p>\n
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That ability to let you know how far your riding partner is behind but also if they are off to one side or the other is the same technology that powers the lane detection and vehicle size features that I suspect most reviews are focusing on. The problem here is that when we move out of the drafting discussion, these features are less useful.<\/p>\n
In both cases you start with slightly expanding the bar that Garmin uses to visualize approaching vehicles. This still turns red, yellow, or green depending on threat assessment (based on approaching speed and now also considering size) and it still has a dot at the top that represents you. What\u2019s new is that the vehicles in this bar now have three icons depending on size and, as long as you have the larger width selected on the headunit, will also show up in different positions horizontally across the bar. This includes partially off the bar, so only half the vehicle icon is shown.<\/p>\n
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This is great for your riding buddy. The small icon is easy to process as being in different spots compared to you and if you are checking to make sure what\u2019s happening with your buddy who\u2019s matching your speed there\u2019s time to figure out what you are seeing. With vehicles it\u2019s less useful. The size is frequently wrong, or it changes size as it gets closer to you, and you don\u2019t always have much time to figure out what\u2019s happening on the screen. What\u2019s important here is the beep (if you have that turned on) or the visual representation of a vehicle. The rest just doesn\u2019t matter much.<\/p>\n<\/figure>\n
All that said, I would bet this is nice on a highway with infrequent semitruck passes. I\u2019ve occasionally ridden in situations like that where I\u2019m sure I\u2019d appreciate this. For most situations though, I don\u2019t find it all that helpful.<\/p>\n
Before I move on I do also want to answer a question about a footnote in the press release. What it said was \u201csame speed tracking is limited or unavailable at slower speeds.\u201d This just refers to the radar needing to be \u201cawake\u201d which happens at 10 km\/h (6 mph). It doesn\u2019t lead to inconsistencies, it just doesn\u2019t work when you are, \u201cpractically speaking,\u201d not moving.<\/p>\n<\/figure>\n
Now, the rest of the features here are mostly expected after a six-year gap in updates. The move to USB-C is the most immediate \u201cthank god\u201d detail, finally aligning this Garmin unit with the rest of the world. Behind that port is a higher-density battery that extends life from the 16 hours of the RTL515 up to 24 hours of day flash. It\u2019s 30-hours if you run it in radar-only mode and, for those who have been clamoring for a leash, it\u2019s finally here. You can now tether the unit to your seat rails for peace of mind on rougher terrain.<\/p>\n<\/figure>\n
The hardware updates aren\u2019t just about endurance. Garmin jumped from 65 lumens to a max of 100 lumens, putting the new unit ahead of the Trek CarBack (90 lm) and Wahoo Trackr Radar (53 lm), though it still doesn\u2019t touch the retina-searing 300 lumens of the Lezyne Radar Drive. Detection is also improved, with range increasing to 175 meters. It still doesn\u2019t match Trek\u2019s ambitious 240-meter claim, but that number hasn\u2019t proven to be real in actual use, partly because Garmin\u2019s communication protocols don\u2019t support it.<\/p>\n
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This is a late addition note as new details have come up on this detection distance: Like Trek, Garmin might also be having issues with that distance. It\u2019s still related to ANT+ technology though, and you should think real hard about buying this unit if that\u2019s your use case. More info below.<\/em><\/p>\n
There are also screws on the back. I\u2019m tempted to tell you that means the battery is user-replaceable, but that\u2019s not quite what Garmin says. The company still officially considers the battery non-serviceable to maintain the IPX7 waterproof rating, so this remains a DIY situation. Despite that, the old one was glued and nearly impossible to reseal. I\u2019d put money on the aftermarket figuring out a replacement kit and seal by the time you need a replacement battery.<\/p>\nThe latest Edge x40 and x50 headunits will use a Bluetooth connection.<\/span> (Photo: Josh Ross\/Velo)<\/figcaption><\/figure>\n
What I don\u2019t like about the Garmin RearVue 820<\/h2>\n
While there\u2019s a lot that changed here, one thing that did not change was the mount. Actually, that\u2019s not completely true. The mounting system that Garmin supplies did change; it just still isn\u2019t that great.<\/p>\n
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The Garmin 515 radar had a \u201cpuck\u201d with inserts for different seatpost shapes and a rubber O-ring to secure it. That O-ring has always been a nightmare to get on and Wahoo showed how much better that type of mount can be.<\/p>\n<\/figure>\n
Unfortunately, Garmin hasn\u2019t really fixed this. The new mount is larger with more surface area against the back of the light. I assume this is an improvement for stability, not that I ever noticed an issue with the old one, but it still uses a similar rubber band to attach it to the seatpost. This time the rubber band is a ladder style so it\u2019s marginally better but you should still expect to spend some time swearing next time you try and get this on. Wahoo added a simple piece of plastic to create leverage and Garmin doesn\u2019t have that. You have to stretch and pray you can manage to get it over the hook.<\/p>\n
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On the upside, once you get it in place, the same quarter turn Garmin mount as before gets it off for charging. Not only does it mean if you only have one bike you almost never have to struggle with that rubber band, but it also means if you already own a third party mount you can keep using it. Alternatively, if you are new to Garmin radar units, go shopping for a different mount. I don\u2019t carry a saddle bag so I am a fan of the kind that attach to the saddle rails but there are a ton of options available.<\/p>\n
Also on my nitpicky list: the RearVue 820 is ugly. I could try and use fancy language to say the design is lacking and the texture of the plastic feels a bit cheap but it doesn\u2019t matter. It\u2019s just ugly and there\u2019s probably a lot of ways it could be fixed.<\/p>\n
I might not have mentioned this, given that it\u2019s highly subjective, but I\u2019ve been hearing from a lot of people on the topic. It turns out I\u2019m actually on the mild end of the spectrum here because I consider a rear radar utilitarian enough that I don\u2019t care too much. Some people seem to care a lot and this isn\u2019t winning any design awards. In retrospect, I think Trek is actually the leader here in terms of industrial design.<\/p>\n
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However, for many, the aesthetic is secondary to the technical ecosystem. The real deal breaker I referenced in the intro is that \u201cadvanced vehicle tracking\u201d is only available on the Edge x40 or Edge x50 series computers. Fortunately this isn\u2019t as bad as it seems. Garmin defines \u201cvehicle size detection, left and right vehicle movement\u201d as the advanced vehicle tracking features. I already told you I don\u2019t think those features are all that important. If you disagree, and you have a bike computer not included in that small group, then this is a deal breaker for you.<\/p>\n
There is actually a little more nuance though. I consider the same speed tracking feature what really sets this unit apart. Specifically because I want to be able to keep track of a friend in my draft. You can still do that without advanced vehicle tracking but if you have it you can also see a friend, or rival, moving around from left to right. There is a distinct advantage to that level of granularity; if you don\u2019t have a compatible computer, you have to decide if the features you still get are enough to justify the $300 price tag.<\/p>\n
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While you make that decision, keep in mind that the technical reason for the limitation is that the newer Garmin units are using a secure Bluetooth connection instead of ANT+. If you expect to use this with ANT+ it will work but not only are you not getting the full breadth of features but there might be issues getting the full detection distance. Think hard about paying for things that you don\u2019t get if that\u2019s your use case. There are other options.<\/p>\n<\/figure>\n
Livability<\/h2>\n
There\u2019s really nothing to fault here. I already discussed the mounting issues and the feature gap on non-Garmin computers, but beyond that, I can\u2019t think of a single missing detail that impacts daily use. I have my computers set to trigger the light in Day Flash mode the moment I hit start and power down when I finish a ride; that automation works fine with Wahoo, Hammerhead, and Garmin units. The transition to USB-C\u2014complete with a more robust port cover\u2014and the inclusion of a leash address long-standing usability complaints. Add in the improved tactile button, the potential for long-term battery serviceability, and a more obvious blue LED to indicate standby mode, and there\u2019s nothing I need to critique.<\/p>\n<\/figure>\n
Who is Garmin RearVue 820 for?<\/h2>\n
If you ride a bike on a road, then a radar is something you should have. The only exception to this would be if you ride exclusively in city traffic. I\u2019m not sure who that would cover, but when there\u2019s always a car behind you, a radar becomes a lot less useful. You can still use it as a mirror\u2014yes, it\u2019s that reliable\u2014but the power of a radar unit is that it\u2019s passive and it alerts you when a vehicle shows up.<\/p>\n
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From there the next decision is Garmin or one of the other radar units in the market? And when I say other units I mean Trek, Wahoo, or Lezyne. There are also a wide range of others that are even cheaper but I\u2019ve tested every single one and found the quality to be all over the place. Some specific units, as in not even all the same model but specific units, work fine and some are dangerously wrong. The question still stands, though: would you pay $300 for a Garmin when you can get a quality unit for $200?<\/p>\n
The real losers in this conversation are actually Wahoo and Trek. Trek is $200 but isn\u2019t a market leader in any feature. It does have a battery gauge, and it looks good, so if that\u2019s what you want then that\u2019s your unit. Wahoo also doesn\u2019t have any category-leading features, but it might still be worth buying because it looks better, it\u2019s cheaper, and it has competitive specs. The problem there is that $250 is cheaper but not as cheap as the competition.<\/p>\n<\/figure>\n
The only time the Wahoo might still make sense is if you want to use a Garmin quarter turn mount but you have an older headunit, or non-Garmin, and can\u2019t take advantage of the Bluetooth connection with added features. The Wahoo light has a technically different mount but it will work just fine in Garmin specific mounts the majority of the time.<\/p>\n
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As long as you can\u2019t take advantage of the advanced vehicle tracking features, and don\u2019t need Garmin mount compatibility, then buy the Lezyne Radar Drive. It has the brightest light of the options and 18-hours of battery life is very good. It also costs $200 and undercuts the Wahoo and the Garmin. The downside of that unit is that the mount is a rubber band style and there\u2019s no possibility of anyone fixing that.<\/p>\n
You\u2019ll want to buy the Garmin RearVue 820 if you have a fairly new Garmin Edge bike computer and want to take advantage of the advanced vehicle tracking features. You will also want to buy the RearVue 820 if you want same speed tracking\u2014the ability to see exactly where a friend or rival is sitting in your draft is a feature no other manufacturer has.<\/p>\n
Like saving money on great gear? Us too. That\u2019s why we developed this<\/i>\u00a0powerful tool that collects the best deals on cycling gear<\/i>\u00a0from across the internet in one convenient, searchable place.<\/i><\/p>\n<\/div>\n
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Josh Ross<\/span><\/div>\n<\/div>\n
Updated February 10, 2026 10:29AM<\/div>\n<\/div>\n
[analyse_image type=”featured” src=”https:\/\/velo.outsideonline.com\/wp-content\/uploads\/2026\/02\/Garmin-RearVue-820-scaled.jpg”] Josh Ross Updated February 10, 2026 10:29AM Pros Same speed vehicle detection 24 hours battery life in day flash mode Includes a leash Replaceable battery Brake light functionality Unchanged Garmin mount Only recent Garmin computers support latest features Cons Visual design is lacking Included mount New features are Garmin only Garmin RearVue […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[226,71],"class_list":["post-1760151","post","type-post","status-publish","format-standard","hentry","category-politics","tag-crawlmanager","tag-velo-outsideonline-com"],"_links":{"self":[{"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=\/wp\/v2\/posts\/1760151","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1760151"}],"version-history":[{"count":0,"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=\/wp\/v2\/posts\/1760151\/revisions"}],"wp:attachment":[{"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1760151"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1760151"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/analyse.optim.biz\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1760151"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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