Trek CarBack Radar Rear Bike Light Review: Impressive Radar Performance and a Light Visible from 2KM

Wisconsin-based Trek has been in business since 1975 and produces a wide range of bicycles, including road, mountain, gravel, and city bikes. They also sell electric bikes as well as a wide range of accessories and apparel. This review looks at the new Trek CarBack Radar Rear Bike Light. As the name suggests, the device combines a rear bike light with a rearward-facing radar that detects oncoming traffic and sends alerts to the rider via several popular GPS cycling computers and smartphones.

The box includes the CarBack Unit, Quick Connect Plus Mount Rear, a USB-C Cable, and the Owner’s Manual.

Trek CarBack Radar Rear Bike Light Design

The Trek CarBack Radar Rear Bike Light measures 2.75″ long by 2″ wide by 1 deep and weighs just over 3 ounces. Its face is made of glossy black plastic with textured rubberized sides and a matte plastic back.

The front panel features a clear rear light lens centered at the top, and the right side has the charge indicator, which is made up of four green LEDs. The right side features the embossed Trek logo.

The Trek CarBack Radar Rear Bike Light has a rubberized power button on the top and a rubber flap on the bottom that covers the charging port.

Pressing the power button cycles through the light’s four modes: Day Steady (maximum output 25 lumens), Day Flash (maximum output 90-lumen bursts), Night Steady (maximum output 5 lumens), and Night Flash (maximum output 5-lumen bursts).

The enclosure has a water ingress rating of IPX7, which protects against immersion in water up to 1 meter for 30 minutes, so riding in the rain is no issue.

The back of the Trek CarBack Radar Rear Bike Light’s case has a slotted mount that slides onto the rubber strap that attaches to your bicycle. This strap is called the Quick Connect Plus Mount Rear and is intended to be mounted to the bicycle’s seat post.

Installation

To work properly, the Trek CarBack Radar Rear Bike Light must be mounted vertically between 27.5″ and 47″ off the ground and not be obstructed by the wheel, fenders, saddle bags, or any other accessory.

I had no issues attaching the unit to any of my mountain bikes and noticed that where the Quick Connect Plus Mount Rear attaches to the light case, the mount is angled to offset the angle of the bike’s seat post. The result is that the radar light is perfectly vertical.

I then tried attaching the Trek CarBack Radar Rear Bike Light to my e-bikes. I have two moped-style e-bikes, which have racks above the rear wheels. In one case, there is also a seatpost-mounted saddle bag, and the other e-bike features a flip-up seat design which allows for the battery to be removed.

In both cases, mounting the radar light to the seat post is not an option without removing an existing component. As the back of both e-bikes have no other vertical posts to which the unit can be attached, I instead tried to attach the Trek CarBack Radar Rear Bike Light to the horizontal bars of the rear racks.

I noticed that the Quick Connect Plus Mount Rear allows for the radar light to be rotated, but the previously mentioned angled bit where the radar light attaches forces the unit to point to one side.

As mentioned earlier, to work as designed, the radar light needs to face directly backward.

My solution was to use two nylon zip ties to attach the Quick Connect Plus Mount Rear to the horizontal bar of the rear rack. This is not as the manufacturer intended, but it allows for full functionality and placement just where it belongs.

Trek offers optional alternate mounts, including the Bontrager Flare Round Mounting Kit ($3.50), which is also intended to be mounted to a vertical post, and the Bontrager Flare Rack Quick Mount Kit ($4.99), which mounts by way of a single screw.

But I believe the Trek Quick Connect Front Light Bracket ($4.99) is the best bet as it is essentially the Quick Connect Plus Mount Rear with the band turned 90 degrees. This makes it ideal for mounting to horizontal bars such as handlebars and rear racks.

Depending on your ride and accessories, you may need to use an alternate mount, and Trek seems to offer options for nearly every situation.

The Trek Accessories App

The Trek CarBack Radar Rear Bike Light is compatible with many popular cycling computers and GPS units, including Garmin, Wahoo, and Hammerhead. It is also compatible with the Trek Accessories app, which is free to download on the Apple App Store and Google Play. I tested the unit with the Trek Accessories app and found it quick and intuitive.

Pairing is simple and takes seconds. Download the app, open it, and press the power button on the radar light. The unit was found immediately and responded with the radar’s display screen and an audible signal in the form of a chime. When the unit is turned on, the light shines a bright red, and the green LED meter on the side indicates the current charge level.

When the unit is shut off, there are a few repeated beeps, and the smartphone’s display shows an image of the radar light with the word “Off” prominently at the top and a battery icon with the percentage of remaining charge on the left.

Performance

Once installed and paired with the app, the Trek CarBack Radar Rear Bike Light starts to sing—almost literally. The device works amazingly well, detecting vehicles from a long way behind you.

I have mirrors on my e-bikes, and I was always surprised by how far back cars were in my mirrors when detected by the radar. Trek states the radar has a detection range of 240 meters or 787 feet. For reference, 787′ is more than two (American) football fields (with end zones)!

Detection comes in two forms: visual and audible. The app display shows three lanes, with the rider in the center lane. The radar has two-axis detection.

As vehicles approach, they are represented by an icon of a car in either black (when they are passing on the right or left of you) or red (when they are directly behind you). Vehicles that are directly behind and change lanes change colors in the app.

When vehicles behind the rider are detected, the app delivers an audible signal of a few quick beeps (the same as when the unit is turned off). After the vehicles have passed, the app provides an all-clear signal in the form of a chime (the same chime played when the unit is powered on).

The Trek CarBack Radar Rear Bike Light’s radar does not give false signals from oncoming vehicles and only responds to those coming from behind the rider. In short, the radar unit works perfectly.

The light is very bright and, according to Trek, can be seen from 1.25 miles (2 km) in the daytime. I cannot verify exactly how far the light can be seen, but it seems effective both day and night.

The lens has focused optics to direct the light beam for increased range. The flash has an interruptive pattern with varying intensity. In all three modes, Night Steady & Flash (5 lumens), Day Steady (25 lumens), and Day Flash (90 lumens), the run time is seven hours.

Trek CarBack Radar Rear Bike Light Specifications

The Trek CarBack Radar Rear Bike Light is a great addition to any bike or e-bike and adds a layer of safety previously unavailable. It is so effective that I recommend that all manufacturers add them as standard equipment. However, as the technology is still fairly expensive and some riders are especially focused on keeping the bike’s weight as low as possible, it makes more sense to have a unit that can be easily moved from ride to ride.

You can’t put a price on safety; the more information you have about what is behind you, the better you can react appropriately. The Trek CarBack Radar Rear Bike Light allows others to see you clearly from a distance and alerts you with plenty of time. It comes with a 30-day unconditional guarantee and is highly recommended.

The Trek CarBack Radar Rear Bike Light retails for $199.99; it is available directly from the manufacturer and other retailers, including REI and Scheels.

Source: Manufacturer supplied review sample

What I Like: Very impressive detection range; Easy and effective app; Bright rear light; Solid yet lightweight construction

What Needs Improvement: I wish a horizontal mounting option was included