RideLoop
Which Garmin Varia radar should you buy?
A rear radar tells you a car is coming before you can hear it: a dot climbs the side of your bike computer's screen and it beeps. Garmin sells four. They split on range, battery, how bright the light is, and whether there's a camera.
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Short version: the Varia RTL515 ($199.99) is right for most riders: radar to 140 m and a tail light that lasts 16 hours in day flash. Get the RearVue 820 ($299.99) for fast roads, dusk and long days: 175 m, a 100-lumen day flash, 24 hours, and a brake light. The RVR315 ($149.99) is radar only, for riders who already run a tail light they like. The RCT715 ($399.99) adds a camera, but only lasts 4 to 6 hours while it records.
Specs side by side
| RTL515 | RearVue 820 | RVR315 | RCT715 | |
|---|---|---|---|---|
| Price at Garmin | $199.99 | $299.99 | $149.99 | $399.99 |
| Sees cars from | 140 m | 175 m, wider view | 140 m | 140 m |
| Tail light | Yes, 65 lm day flash | Yes, 100 lm day flash, brake light | No | Yes, 65 lm day flash |
| Seen from | 1.6 km (1 mi) | 2 km (1.24 mi) | No light | 1.6 km (1 mi) |
| Battery, day flash | 16 h | 24 h (30 h radar only) | 7 h (radar) | 6 h, recording 1080p |
| Battery, solid light | 6 h | 10 h | No light | 4 h, recording |
| How it rates a car | By speed | By speed, size and how close it passes | By speed | By speed |
| Camera | No | No | No | 1080p or 720p |
| Weight | 71 g | 90 g | 51 g | 147 g |
| Water rating | IPX7 | IPX7 | IPX7 | IPX7 |
| Shops |
Figures are Garmin's own; battery depends on the light mode and the temperature. Prices are Garmin's list prices; shops often sell the older models for less.
What a radar does, and doesn't
The radar sits on your seatpost and watches the road behind you. When a car comes up, your Edge shows it as a dot moving up the side of the screen, colored by how fast it's closing, and beeps; the light flashes harder as the car gets near. On a quiet road you hear about every car long before it reaches you, which makes it much easier to hold your line, wait for a gap before a left turn, or ride two abreast and single up in time.
It doesn't see a car that's level with you, it doesn't steer anything, and it doesn't replace looking over your shoulder. It's most useful on exactly the roads riders like: quiet country roads where cars are few but fast.
Every current Edge shows Varia radar, and so do select Garmin watches and the free Varia app on a phone. Bike computers from other brands that support ANT+ radar, Wahoo's ELEMNT among them, can show it too.
Varia RTL515: the default
The one most riders run. Radar to 140 m, a tail light visible from a mile, and 16 hours in day flash, which covers a long day out or a week of commutes between charges. At 71 g it's light, and it's been around long enough that shops often sell it below Garmin's $199.99. It rates cars by speed only, and its light is dimmer than the 820's.
RearVue 820: the upgrade
Garmin's newest radar sees cars from 175 m with a wider field of view, so a fast car shows up sooner and a car coming round a bend is less likely to be missed. It rates cars by size and by how close they pass as well as by speed, so a truck reads differently from a car. The light is Garmin's brightest, 100 lumens in day flash, seen from 2 km, with a brake light that comes on when you slow. Battery is the other gain: 24 hours in day flash, 30 with the light off.
It costs $100 more than the RTL515 and weighs 90 g against 71. Worth it if you ride fast roads, ride at dusk, or ride days long enough that the RTL515 would need a charge.
RVR315: radar, no light
The same 140 m radar with no light, at 51 g and $149.99. It makes sense if you already run a tail light you trust and just want the warnings. Its 7-hour battery is the catch on long days; the RearVue 820 runs 30 hours with its light off.
RCT715: the camera
The RTL515's radar range and light output with a camera behind you: 1080p or 720p at 30 frames a second, recording all the time or only when the radar sees a car, and it locks the footage when it detects an incident. The trade is battery and weight: 4 to 6 hours while recording, and 147 g. Pick it if footage of close passes or a crash matters to you, and your rides fit inside its battery.
Which to buy
- Most riders, most roads: Varia RTL515.
- Fast roads, dusk, or all-day rides: RearVue 820.
- You already have a tail light you like: RVR315.
- You want video of what's behind you: RCT715, on rides under about 5 hours.
- No bike computer yet: start with the right Edge; every current one shows the radar.
How long your rides run decides the battery you need: how long a ride takes has a calculator.
Radar plus quieter roads
A radar tells you about the cars that are there; the route decides how many there are. RideLoop builds loops on roads riders and AI have graded for shoulders, traffic and surface, and sends them to your Garmin, so the dot on the side of your screen shows up less often. More on picking roads in how to find bike-friendly roads.
Questions
Is the Varia RearVue 820 worth it over the RTL515?
If you ride fast roads, ride at dusk or ride long days, yes: it sees cars from 175 m instead of 140 m, its day flash is 100 lumens instead of 65, it lasts 24 hours in day flash instead of 16, and it adds a brake light. For shorter rides on quieter roads, the RTL515 does the same job for $100 less.
Does a Varia radar work without a Garmin Edge?
Yes. The free Varia app shows approaching cars on your phone, and select Garmin watches show them too. Bike computers from other brands that support ANT+ radar, Wahoo's ELEMNT among them, can show it as well.
How long does a Varia radar battery last?
Garmin's figures: RearVue 820, 24 hours in day flash (30 hours radar-only); RTL515, 16 hours in day flash; RVR315, 7 hours; RCT715, 6 hours in day flash with the camera recording 1080p.
Which Varia has a camera?
Only the RCT715. It records 1080p or 720p video behind you, can start recording when the radar sees a car, and locks the footage when it detects an incident. It costs $399.99 and runs 4 to 6 hours while recording.
Fewer cars to watch for
Pick a start and a distance. RideLoop builds the loop on graded roads and sends it to your Garmin.
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