BQ Tests: Radar Rear Lights

A set of lights on your bike for daytime use makes a lot of sense. Whether you end up in a low light situation, or just want to ensure your visibility to other road users, daytime running lights are an easy addition to your bike. In many countries, vehicles have to have them fitted by law.  

The past few years have seen an increase in the functionality of rear lights on bikes. There are now options for bike lights with integrated cameras, models with accelerometers to react to braking, and as shown here – bike lights with radars. The idea behind having a rear light with a radar is that it can alert you to a vehicle approaching, with a visual and/or audible alert to your compatible bike computer, smart watch or smart phone. While this can be achieved with a helmet or handlebar mounted mirror, that won’t suit everyone. And in the same manner, a radar light won’t be for everyone either. 

TESTING 

I tested these four units paired to a Wahoo ELEMNT Bolt bike computer. You can look up the compatibility for each unit on the manufacturer’s website. I tested the units on a mix of separated bikeways, hilly mountain roads, gravel roads, busy urban roads and rolling country roads. 

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Trek Carback
$299.99 | 100gm 
trekbikes.com 

Trek’s Carback has its own app, or pairs to a wide variety of bike computers. Along with a claimed 240m radar range, Trek state their light is visible upto 2km away – perfect for daytime running. The unit itself has a battery indicator on the side, and has a short overall length, which may help it fit on smaller bikes while still being visible. Trek also have mounts for some Bontrager saddles, to ensure your rear wheel doesn’t obscure the light or radar. Trek’s app will show precise distances and even lane position of an approaching vehicle, but I found the data on my Wahoo was perfect. 

I have found the Trek Carback to be very precise and also great with early detection. The mount is not my favourite as it is very difficult to remove the light from the mount to charge, and the mount isn’t that secure on a 27.2mm seatpost that is typical on many road or gravel bikes, without overstretching the elastic.

If a light like this twists on a post – it cannot be useful. While the bright light can reduce running time, via the day, night and steady run modes you can achieve up to 7 hours run time. This is great product with a very bright light mode amongst others, but perhaps best suited to riders with Bontrager saddles where they can attach the light in the most visible and secure location – or for bikes with seatposts larger than 27.2mm.

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Bryton Gardia R300L 
$199.95 | 101gm 
brytonsport.com.au 

Bryton are known for their bike computers but have created this radar light as well, with some nifty features. The Gardia R300L will pair with their own popular bike computers, others on the market or their own app for those using their phone. What’s really cool is how the light uses movement sensors within the device to power on and off after breaks, and it also changes the light mode when sensing vehicles. There is also a light sensor, so the light will use the daytime setting when there is adequate light, and boost the light available when it gets darker. One last trick is acting as a brake light, with the light output changing as braking is sensed. It’s a smart piece of kit!

The radar picks up vehicles up to 190m away, and like other units you’ll get a visual and audio alert via your device, depending on your preferences. Like most radar lights the light is at the top and the radar below, so you need some post exposed to ensure it is visible, not behind a tyre, rack or luggage.

The mount is very easy to fit to a round, square or aero post, with a 90 degree turn to attach it. I really like the shape and different functions of the Gardia R300L, but despite ever changing road conditions it didn’t pick up vehicles quite as quickly as the Trek light. However, with visibility claimed at 1.6km and a light running time of 12hrs+, at $199.95 and with it’s unique features and app it sure has a lot going for it. 

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Magene L508 
$199 | 83g 
FEsports.com.au 

Magene are making all manner of electrical goodies, and this radar light is one of them. It also has it’s own app, allowing customisation of all the modes around their brightness and whether the radar and brake warning are engaged. Like others, the Magene L508 does flash an alert for 2 seconds to an approaching car, and it does a similar alert when hauling on the brakes. 

The mount works for square, round and aero posts, using a simple but proven O-ring to attach. It’s easy to replace if broken, but not as easy to remove. The light has a simple 90 degree turn to release. While this unit paired just as easily as all the others, it has a maximum range of 140m, which is considerably less than some.

When riding with my partner I could hear the alert from her unit and count a few seconds until the Magene picked up the same vehicle. Of course, longer range won’t be that useful on twistier or hillier roads, and the Magene does have a long battery life of 12hrs+, depending on modes used. It never missed a large vehicle, but rarely picked up motorbikes – and the shorter range means it just didn’t pick things up as soon as others. I think the customisation on this light is a real bonus.

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Garmin Varia RCT715 
$699 | 201g 
garmin.com 
 
The Garmin Varia was an industry leader, bringing a rear light and radar together. As you can see, the market has grown. And in that time, Garmin have updated their range, including the Varia RCT715 on test here, with a built in camera that offers incident recording. It does mean the whole unit has gained weight, and the light has a very robust attachment to ensure it stays put on a variety of posts, and the light is mechanically locked onto the mount. 

The camera doesn’t need to be used, or it can be run continuously or on incident detection, where it records immediately before, during and after the incident, with a date and time stamp. Plus location if possible. Depending what camera setting you use, and light mode, you can get 4-10 hours battery life. Claimed visibility is up to 1.6km, it isn’t as piercing as the other lights on a driveway test, yet is clearly visible in use. 

In use, the 140m radar range is good and I’d even suggest it picks up more than that on a straight road. The incident detection and camera is an interesting addition. More control can be gained with a Garmin device, although I did get an incident recording from a poorly timed speed bump bunny hop. The app is ok for collecting this, but I think compared to not having the option it is worthwhile. The GoPro Quik app is far better for accessing footage from a device like a GoPro, but for incident detection this is very useful. It’s a big unit and does use a lot of battery – but I think this combination could offer great peace of mind for many riders.

Do you want more peace of mind when riding? Check out the extensive insurance coverage included with Bicycle Queensland membership.