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We’ve got been ready for a brand new era of the Garmin Varia RTL515 radar for a few years, virtually 6 (!) to be precise (not counting the RCT715). Everyone hoped for only a gradual improve in battery life and a USB-C port. However Garmin cooked one thing stunning. The RearVue 820 comes with a few new options, however the query is whether or not they’re really definitely worth the worth enhance. On this assessment, you will discover out.
KEY TAKEAWAY
Garmin RearVue 820 takes the top-notch accuracy of the earlier Varia fashions a step additional. It will possibly acknowledge car dimension and lane, offering you with much more info. Whereas spectacular on paper, in actuality, I discovered this a bit distracting as a result of I didn’t need to hold glancing at my bike pc display screen to see what sort of car was approaching. All I needed was Varia RTL515 with a USB-C port at an identical worth level, and I’d be pleased.
Sadly, the RearVue 820 is simply too costly. So, regardless of it undoubtedly being probably the most succesful radar in the marketplace, I imagine there are alternate options providing a greater price-to-value ratio, such because the Wahoo TRACKR Radar or Sigma RECO 81. In the event you determine to purchase it anyway, you should buy it right here or proceed studying for more information.
My RearVue 820 score at a look:Reliability 5/5 | Multi-object Detection 5/5 | Battery Life 5/5 | Brightness 5/5 | Facet Visibility 5/5 | Mount 4/5 | App 4/5 | Worth 1/5 | WEIGHTED OVERALL SCORE 4.4/5More about this biking radar scoring.
Because of Garmin Czechia for lending the radar for this assessment.
NOTE: I examined this radar with firmware v6.34 and Edge 1050 v30.18.
Garmin RearVue 820 Abstract
Beneath is a abstract of the Garmin RearVue 820 technical specs.
Garmin RearVue 820 Technical Specs
Dimensions: 98.9×25.9×43.2 mm
Weight: 90g
Claimed battery life: as much as 24 hours (day flash)
Actual battery life: 18 hours (day flash)
Charging: USB-C
Radar: Sure
Taillight: Sure
Brake sensing: Sure
Auto standby: Sure
Lumens: as much as 100
Water resistance: IPX7
Detecting distance: 175m
Detecting pace: n/a
Viewing angle: 220°
Horizontal angle: 60°
Protocols: ANT+, Bluetooth
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What’s New In comparison with Garmin Varia RTL515?
There are extra upgrades to the RearVue 820 than it may appear at first look. Right here is the whole listing:
RearVue 820 will increase the detection vary from ~140 m to ~175 m.
The 820 widens the radar beam from ~40° to ~60°.
New menace logic elements in car dimension (small/medium/massive) and lateral motion, not simply pace.
RearVue 820 gives the identical speed-tracking, displaying riders or automobiles behind you shifting at an identical pace, whereas the RTL515 typically drops them.
Visibility and brightness are meaningfully improved:
Day‑Flash jumps from ~65 lm on the RTL515 to ~100 lm on the 820.
Claimed visibility will increase from as much as ~1.6 km to as much as ~2 km in daylight.
Battery life is longer throughout all modes:
Stable mode goes from ~6 h to ~10 h.
Day Flash extends from ~15–16 h to ~24 h.
A devoted radar‑solely mode can run for about 30 h.
The 820 provides USB‑C charging and a consumer‑replaceable battery pack (rear cowl with screws).
Mild modes are the identical primary set as on the RTL515, however now embrace customized flash patterns and brightness profiles created within the Varia app and synced to the sunshine.
Built-in brake‑gentle habits makes use of the unit’s accelerometer to briefly increase brightness while you sluggish or cease.
Mild controls at the moment are additionally uncovered over Bluetooth, giving telephones and a few watches higher integration than on the RTL515.
The unit is barely bigger and heavier (from ~71 g to ~90 g) however stays compact and IPX7‑rated with an identical seatpost‑mount kind issue.
The 820 is priced increased than the RTL515 ($299 vs. $199).
My Expertise with Garmin RearVue 820
Based mostly on my testing, I discovered the next professionals and cons of the RearVue 820.
RearVue 820 Professionals
Offers virtually no false positives (near 0)
Can detect car dimension and lane, and automobiles touring on the identical pace
Improves aspect visibility
Provides an extended actual detection distance than most radars in the marketplace
Modifications the sunshine sample throughout your entire overtaking interval
Options brake sensing, standby, and battery life indicator
Design permits simpler battery replacements
Security tether is included
RearVue 820 Cons
The mount appears overengineered and is ineffective for some seatpost varieties
Identical-speed car monitoring generally results in false menace alerts
Requires Garmin Edge x40 or newer, or Discover 2 for the total characteristic set
Excessive worth
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Unboxing and Setup
Simply primarily based on the field contents, it’s clear that Garmin studied critiques of different biking radars: you’ll discover a security tether inside (it wasn’t included within the Varia RTL515 field), and the mount has been redesigned to stop slipping on a seatpost. There are a number of adaptors included, these appropriate for an aero seatpost, rounded and D-shaped ones, and two rubber straps to permit tightening the mount.
As all the time with bicycle radars, I first checked for firmware updates by way of the Varia app. Nevertheless, I couldn’t flip the radar on. The crimson LED standing indicator was flashing slowly, which I took as an indication that the battery was low and wanted charging. However even after plugging it into the charger, it saved flashing in the identical sample. So I appeared into the assist part and discovered that the radar had doubtless gotten caught in “error mode.” I had by no means encountered something like this earlier than. I needed to exhausting reset it (holding down the facility button for about 15 seconds). After that, the sunshine stopped flashing, and I might recharge the radar.
After charging, I attempted to put in the firmware v6.34 replace by way of the Varia smartphone app, however encountered one other drawback. Though the replace had downloaded and the app confirmed that it was downloaded, the LED indicator on the radar saved flashing orange and inexperienced for greater than 10 minutes. That appeared too lengthy to me, so I used the Garmin Categorical macOS app to replace it over a wired connection, and the firmware replace accomplished in about 5 minutes.
I then paired the radar with the Garmin Edge 1050. Nevertheless, I noticed the previous bar with dots, not the brand new one which exhibits car sizes and lanes. This was as a result of my E1050 had firmware 29.22, however assist for car dimension detection is offered solely in variations 30.18 and newer. So, be mindful to replace it! When you do, you will notice the Radar View data while you pair it. In the event you had the radar paired and you continue to see the previous automobile dots after the firmware replace, unpair it and pair it once more.
Detection Accuracy
Since I’ve wealthy expertise with the Varia RTL515 (and I additionally examined the Varia RCT715), I had a reasonably good concept of what to anticipate. And RearVue 820 didn’t disappoint.
RearVue 820 has a 60° subject of view, which is 20° greater than most different radars. From the radars I just lately examined, solely Sigma RECO 81 gives the identical subject of view. Which means that the radar covers a broader “hall,” catching automobiles in adjoining lanes or drifting over sooner. That is helpful on multi-lane roads or throughout overtakes.
Talking of multi-lane roads, RearVue 820 can acknowledge which lane the automobiles are in, after they change lanes, and in addition their dimension. All this whereas detecting them a bit sooner, because of as much as 175m detection vary. What does this imply in apply?
Effectively, lane detection isn’t as helpful as you may assume. Why, you ask? When site visitors is heavy, you don’t have time to continuously test your bike pc display screen. You need to look forward. The flexibility to detect lanes is perhaps useful in some situations, however since we don’t have too many four-lane roads right here (and I basically attempt to keep away from them), I discover this characteristic a bit ineffective. In the long run, I need the radar to alert me about automobiles which may threaten me, not people who drive in a second line (from my view). And that is one thing RearVue 820 does properly, particularly because of its prolonged detection vary, which alerts me 2-3 seconds prior to radars with a detection vary of round 140m.
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Nevertheless, probably the most important, but in addition polarizing, improve is the brand new same-speed car monitoring. In earlier generations (RTL515, RCT715), the radar labored totally on “relative velocity.” If a automobile slowed down and matched your pace precisely whereas ready to move, it could typically “ghost” or disappear out of your head unit completely. The RearVue 820 solves this security hole by sustaining a lock on the goal even when the pace differential drops to zero. By way of pure security, it is a win; you’re by no means left questioning if the automobile behind you turned off or is solely hovering in your blind spot.
However this technical precision comes with a trade-off. As a result of the 820 is so delicate to things shifting at your tempo, it generally acts as a “drafting” sensor. You probably have a pal sitting in your wheel, the RearVue 820 generally detects him as a “menace” and retains them pinned to your display screen at some point of the journey. Whereas the RTL515 was ignoring objects touring on the identical pace (viewing them as a part of your “pack”), the 820 is way extra literal.
These “pretend threats” are technically not false positives, however they generally get caught on my bike pc display screen. This may result in a little bit of “alert fatigue” the place you begin tuning out the radar when an actual automobile lastly approaches.
Battery Life
The battery is meant to last as long as 24 hours in day flash mode. I examined it in actual circumstances, and it lasted ~18 hours. That’s sufficient for per week of in depth using. Because of USB-C, you possibly can recharge it from 0 to 100% in about 2.5 hours; nonetheless, the primary quarter-hour of charging provides you with at the very least 2 hours of battery life. Additionally, needless to say as soon as the temperature is beneath 20°C (68°F), the charging pace is routinely lowered to guard the battery. The next chart exhibits the claimed and actual battery lifetime of the chosen alternate options.
Surprisingly, it doesn’t have an Auto Sleep characteristic that places it right into a stand-by mode after a number of minutes of inactivity, like another Chinese language alternate options. Nevertheless, it helps auto stand-by, that means that while you finish your exercise or flip off your bike pc, the radar turns off as properly. And while you activate a brand new exercise or bike pc, it is going to get up with the final mode used. That is one thing I actually miss on the Sigma RECO 81.
Brightness
RearVue 820 has glorious brightness. It’s even increased than Garmin Varia RTL515 and another radar I examined. The next photograph compares the Garmin RearVue 820, the Wahoo TRACKR Radar, and the Garmin Varia RTL515.
The radar adjustments the flashing sample all through your entire overtaking interval. It additionally options the brake gentle, that means the radar will change the sunshine sample as you brake to alert drivers behind. Lastly, it has aspect LEDs that enhance aspect visibility. All packing containers checked right here!
Smartphone App
The Varia app gives extra choices than the RTL515. You may preview and switch gentle modes on and off, and design your personal flashing sample. I discover the default ones adequate, however you possibly can let your creativity free.
Naturally, the app can exchange a motorcycle pc as a result of it will probably show details about automobiles. I don’t know many individuals who would use a $299 bike radar with a smartphone, nevertheless it’s good to have this flexibility.
Mount
I had excessive expectations for the redesigned mount as a result of the previous one was fairly free. Sadly, regardless of its bulkiness, it doesn’t work properly on sure seatpost varieties. For instance, I’ve an aero seatpost, however the aero adaptor merely doesn’t match properly; it’s higher to make use of the opposite two adaptors.
Attaching the mount with the lengthy rubber strap is fairly difficult to deep seatposts. I desire the Wahoo or Sigma mounts as a result of they let me tighten them as wanted, they usually don’t slide. So, regardless of Garmin’s efforts, I discover the brand new mount fairly disappointing.
By the way in which, you could have seen that the adaptors are marked with 73° and 77°. This ensures that the radar is ideally perpendicular to the bottom, relying on the seatpost angle. This looks as if a intelligent resolution to a uncommon drawback. However the fact is that the right radar place might be the second most vital factor (after dialed firmware) to make sure excessive detection accuracy.
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Garmin RearVue 820 vs. Different Biking Radars
The next desk summarizes the technical specs of the RearVue 820 and different common bicycle radars.
Function/RadarDimensionsWeightClaimed battery lifeReal battery life (day flash)Charging portBrake sensingAuto stand-byCustomizable gentle modesLight sample change when overtakingApp can exchange a motorcycle computerLumensDetecting distanceRelative detecting speedWater resistanceViewing angleHorizontal detection angleProtocolsDetecting frequencyMount standardMore InfoBuy
Varia RTL51598.6×19.7×39.6 mm3.9×0.8×1.6 in71g16h flash 22h radar solely 9.5¹MicroUSBNoNoNoYesYesUp to 65Up to 140m10 to 160 km/h(6 to 99 mph)IPX7220°40°Bluetooth, ANT+~24 GHzGarminRTL515 reviewCheck PriceCheck Worth (rei.com)
Magene L50894×25×38 mm3.7×0.98×1.5 in65g15h flash19h radar only7.3USB-CYesYesYes³YesNoUp to 40Up to 140m10 to 120 km/h(6 to 74 mph)IPX7220°40°Bluetooth, ANT+24.05 – 24.25 GHzGarmin-like rotated 90°L508 reviewCheck Worth
Bryton Gardia R300L97×20.9×40 mm3.82×0.82×1.57 in66g17h flash 24h radar solely 11.7²USB-CYesYesNoYesYesUp to 73Up to 190m10 to 120 km/h(6 to 74 mph)IPX7220°40°Bluetooth, ANT+~24 GHzGarmin-like rotated 90°R300 reviewCheck Worth
iGPSport SRTL SR3099×20.3×39.7 mm3.9×0.79×1.56 in68.8g12h flash 20h radar solely 16.9USB-CYesYesNoYes (only for a couple of seconds)YesUp to 65Up to 150m10 to 120 km/h(6 to 74 mph)IPX7220°40°Bluetooth, ANT+~24 GHzGarmin-like rotated 90°SR30 reviewNot advisable
Trek CarBack70×30×50 mm2.76×1.18×1.97 in70g12h flash11.3USB-CNon/aNoNoYesUp to 90Up to 230m⁴n/aIPX7n/an/aBluetooth, ANT+~77 GHzProprietaryCarBack reviewCheck PriceCheck Worth (trekbikes.com)
Magicshine R30096×29×34 mm3.78×1.14×1.34 in110g16.2h flash 26.3h radar only9.4USB-CNoYesNoYesNoUp to 300Up to 140m10 to 160 km/h(6 to 99 mph)IPX6270°35°Bluetooth, ANT+24 – 24.25GHzProprietaryR300 reviewNot advisable
Cycplus L776.5×25×37 mm3×0.98×1.46 in67g25h flash 36h radar solely 15.3USB-CYesYesNoYesNoUp to 40Up to 160m6 to 160 km/h(3 to 99 mph)IPX6270°40°Bluetooth, ANT+n/aGarminL7 reviewNot advisable
Wahoo TRACKR77×19×37 mm3.03×0.75×1.46 in99g15h excessive flash36h radar only8.5USB-CYesYesNoYesNoUp to 53Up to 150mn/aIPX7n/a35°Bluetooth, ANT+~24 GHzGarmin⁵TRACKR Radar reviewCheck Worth
iGPSport SR mini77×37×19 mm3.03×1.46×0.75 in50g7h day flash25 radar solely 8.6USB-CYesYesYesYesYesUp to 30Up to 160m4 to 110 km/h(2 to 68 mph)IPX7220°45°Bluetooth, ANT+n/aGarmin-like rotated 90°SR mini reviewCheck Worth
Coospo TR7096×23×39 mm3.78×0.91×1.54 in65g30h flash 40h radar solely 19.5USB-CYesYesYesYesYesUp to 70Up to 140m6 to 128 km/h(3 to 79 mph)IP67220°40°Bluetooth, ANT+n/aGarmin-like rotated 90°Coospo TR70 reviewNot advisable
Sigma RECO 8198.6×19.7×39.5 mm3.88×0.78×1.56 in62g21h flash 30h radar solely 14.5USB-CYesYesYesYesYesn/aUp to 160m5 to 165 km/h(3 to 102 mph)IP67220°60°Bluetooth, ANT+n/aGarminSigma RECO 81 reviewCheck Worth
Garmin RearVue 82098.9×25.9×43.2 mm3.9×1.0×1.7in90g24h flash30h radar only18USB-CYesYesYesYesYesUp to 100Up to 170mn/aIPX7220°60°Bluetooth, ANT+n/aGarminRearVue 820 reviewCheck Worth
This desk compares options of the chosen bicycle radars.¹About two years previous unit. The battery depreciation most likely influenced the battery life.²Demo unit – I’m not certain if this influenced the battery life. ³Paid subscription or free for e mail subscription.⁴The actual detecting distance is round 150m, which suggests kind of the identical as different radars.⁵TRACKR Radar received’t match Garmin mounts resulting from wider socket.Up to date: March 6, 2026
Issues to Think about Earlier than Shopping for a Bicycle Radar
Biking radars should be extremely dependable. They could provide you with false positives, however they need to by no means provide you with false negatives, which suggests they by no means miss a automobile.
You must have zero tolerance for false negatives should you purchase a tool like a biking radar. Nevertheless, you shouldn’t rely completely on a bicycle radar, however you also needs to use your different senses whereas using.
Based mostly on my testing, the RearVue 820 by no means missed a automobile and proved to be the most effective biking radars I examined.
My Verdict
After speaking to engineers from Terasilic, the provider of sensors utilized in many bicycle radars, and studying extra technical particulars about how the bicycle radars really work, I like Garmin for growing a radar that may precisely assess car dimension and lane. Based mostly on my expertise with Chinese language radars, which regularly give too many false positives, reaching such precision and accuracy just isn’t commonplace in any respect and raises the bar even increased.
The battery life, the sunshine’s visibility even from aspect angles, and the longer detection vary are additionally spectacular. Garmin tried to enhance the mount, nevertheless it’s fairly cumbersome and never appropriate for some seatpost varieties. This can be a bit disappointing. Nonetheless, RearVue 820 achieved the very best score of all of the radars I’ve examined thus far. So, is it a transparent advice?
Effectively, not fairly. I feel it’s a little bit of overkill, at the very least when it comes to worth. In the event you don’t thoughts spending 50% greater than on the Varia RTL515, you’ll undoubtedly be proud of it. However if you wish to lower your expenses, I’d take into account alternate options (just like the Wahoo TRACKR Radar) that don’t provide such superior detection, however in the long run, it doesn’t matter a lot as a result of they’re completely enough for his or her goal. I used to be additionally disillusioned by the preliminary setup points. I’m certain that much less tech-savvy customers would wrestle with discovering options to them. Lastly, “same-speed car monitoring” can result in a selected kind of “false positives” throughout group rides, inflicting a relentless dot on the bike pc display screen that represents different cyclists.
I want Garmin would launch a stripped-down model of this radar—one which’s smaller, doesn’t have lane detection, and, most significantly, is half the worth. However I don’t assume that’s going to occur.
In the event you determine to purchase the RearVue 820, please take into account clicking the hyperlinks beneath. It received’t value you something further, and it’s one of the best ways to assist this web site. Thanks very a lot prematurely.
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Garmin RearVue 820 FAQ
The product for this assessment was kindly supplied by the producer. This didn’t affect my total verdict or my opinion in regards to the product. You may study extra about how I method critiques right here.
