If you ride your bike on roads often, especially in busy traffic, you’ve likely had some close calls — or at least some vehicles that have come a bit too close for comfort. A number of bike radar devices are available these days that are a bit like having eyes in the back of your head. They let you know via both a visual and sound alert on your phone app or bike computer that a vehicle is approaching behind you. Most, but not all, serve double duty as tail lights. One, the Garmin Varia RCT715 which we reviewed here (with some video clip included) will also record videos, either by choice or in the case of an incident.
This post is just about some of the various devices available on the market. We haven’t tested them all. And it includes some affiliate links, which means that if you click a link and make a subsequent purchase we may get a small commission that helps to offset the costs of running this site.
Incidentally, I decided to try my hand at AI image generation via Canva for this post as I didn’t want to use the same photo for everything. The text “Digital art style image with a woman on a pink bike with rearview bike radar and an approaching cute car” generated the hot pink featured image, rather than a woman on a pink bike, but I decided to just go for it.
Table of Contents
Bike Radar Units on Amazon
Garmin Varia
The primary maker of bike radar devices is Garmin. And, as you can imagine, the devices pair well with the Garmin Edge series of bike computers. Using them with an Edge device allows you to both get alerts and to control the various features of your device. You can also do so by using the Varia app, though I don’t like its interface and feedback as well as other devices and apps.
You can also use a Wahoo bike computer with these, pairing them via ANT+ and a couple of phone apps — Ride With GPS and Cadence — will also pair with Garmin Varia Devices. However, you won’t be able to control the device features, such as camera or lights, from these apps.
Garmin Varia RCT715
Buy on Garmin | Buy on Amazon | Read our Review
We own the Garmin Varia RCT715 and reviewed it here, though we’re not sure we really need the video feature. This is the most feature-rich of Garmin’s radar devices, including both the light and a camera which will record still photos or video and has incident detection which is supposed to start saving a video clip if it detects an incident.
Weight weenies will note that it’s the heaviest and largest of the Varia devices.
You might also want to note that this comes with its own mounting system. Other devices like the RTL515 use the same quarter-turn mount that Garmin’s Edge computers use. Therefore, it’s somewhat easier to find alternate mounts for these devices.
If you use a standard seatpost
The seatpost is a tube that extends from the bike frame's se... and aren’t prone to stacking stuff up on the back of your rear rack, you’re in luck: it’s easy to install using the seatpost mount that comes with silicone straps — I believe all the Garmin devices come with a similar seatpost mount setup.
But if you have a dropper postA dropper post is a type of bicycle seatpost that can be rai..., you may need to get more creative in your installation of this light. If you’re interested in that, read our post about how we mounted the light in different places on our two bikes which both have dropper posts and rear racks.
It’s also, of course, the most expensive of the radar devices, generally selling for $399 unless you can find it used or on sale.
Garmin Varia RTL515
The Garmin Varia RTL515 is much like the Garmin Varia RCT715 except it doesn’t have the camera feature, making it a bit smaller and lighter. In our review of the RCT715 that we mentioned previously, we have a weight comparison chart.
This one generally retails for around $199.
Garmin Varia Rearview Radar
This unit comes with a tail light device which you can purchase either on its own or with a head unit which will show you approaching vehicles if you do not have or want to use a bike computer or phone app.
The tail light alone costs about $199, while the package of both head and tail unit costs $299 at the time of this writing.
The tail light on this one brightens and flashes when it detects traffic approaching.
Garmin Varia RVR315
If you already have a rear bike light and don’t care about video features, the Garmin Varia RVR315 will give you the rearview radar in a smaller, lighter package.
And, of course, it’s more affordable. At the time of this review, it is retailing for $149.99
Garmin Varia eRTL615
I was curious what was “E” about the eRTL615. It turns out that it plugs into compatible ebikes so it keeps that light charged.
To connect it, you’ll need to purchase a compatible Garmin cable. The compatible bikes they mentioned are Bosch and Shimano ebikes. So you might have trouble connecting one to your Specialized Turbo ebike.
As it integrates with (some) ebikes, you can expect that it would be more on the pricey end of things. At the time of this post, it’s retailing for $299.99.
Other Brands
Not all cycling radar devices are Garmin. You’ll find other devices from one-off retailers. Note that we haven’t had the opportunity to test all of these devices ourselves.
Many of them cost much less than comparable Garmin devices. Most will also have the same issues with installation — for instance needing to figure out alternate ways to install them if you use a dropper post.
Bryton Gardia R300L
As far as we can tell, Bryton makes but one radar device at the time of this writing and it’s the R300L.
This one ranges in price from $109-95 – $129.95 so it’s significantly less expensive than the comparable Garmin RTL515. It appears that the interface and alerts are also similar to the Garmin units.
While it says that it will pair with the Bryton Gardia app or a Bryton bike computer, responses from buyers on Amazon also indicate that it will pair with Garmin Edge computers as well.
The battery life on this may be comparable, or even better, than a Garmin unit…but that, of course, also depends on how you’re using it. The large Garmin RCT715, for instance, boasts video features that suck battery life out of it. This unit does not include that, so you can expect battery life to be better in comparison.
The rear light, I believe, is about 78 lumens — so pretty bright for visibility.
iGPSPORT SR30
This one ranges from $139.99-$159.99 at the time we’re writing this post. Like most of the Garmin devices, this one has several different light modes that you can cycle through.
It pairs with the iGPSPORT bike computer or app — but it says that it will connect to any bike computer with “standard connection protocols.” So it should connect to your bike computer.
Reviews on Amazon have been very positive for this one, with many reviewers comparing it favorably with Garmin Varia devices.
Magene L508
The Magene bike radar tail light appears similar to many of the other units in that it has several different light modes available.
It has fairly high reviews on Amazon but not quite as high as the other units mentioned here previously.
The light will flash to when it senses approaching traffic as an extra warning.
You can use Magene’s app or computer, but it also will pair with Garmin Edge devices, with Byrton devices, or with Wahoo Roam or Bolt devices (we’re not sure about the Elemnt).
