Bicycles

Trek's CarBack bike radar gives next-level warnings on what's behind you

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The Trek CarBack is priced at US$199.99
Trek
The Trek CarBack's LED battery level display
Trek
The Trek CarBack is IPX7 waterproof
Trek
The Trek CarBack is claimed to tip the scales at 87 grams
Trek
The Trek CarBack is priced at US$199.99
Trek
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If you're worried about being unexpectedly overtaken by cars while you're cycling, Trek's new CarBack may be just the ticket. It's not the only bicycle radar device on the market, but it is claimed to be the best in several ways.

We first heard about the concept of rear-facing radar for bikes back in 2014, with the unveiling of the Backtracker. Just a year later, the technology was licensed to Garmin, which now uses it in the Varia Radar system.

A couple of other manufacturers have come out with their own setups, plus some have built radar systems right into their bikes. Trek, however, is the biggest and best-known company to have gotten on board since Garmin did nine years ago.

CarBack works much like Varia, in that it takes the form of a rear-facing seatpost- or saddle-mounted module that sends out radar pulses which echo off any cars within a set distance behind the bike. The module receives those echoes and analyzes them to determine how far away each vehicle is, and how fast it's closing in.

Users are alerted by an audible alarm on their ANT+ or Bluetooth-paired cycling computer or smartphone, which also provides a visual display on its screen. That display shows how many vehicles are present, how far away they are, and how fast they're closing in.

The Trek CarBack is claimed to tip the scales at 87 grams
Trek

Most major brands of cycling computers should be compatible, including Wahoo, Hammerhead and (a bit ironically) Garmin. Smartphone users link up with the CarBack via the iOS/Android Trek Accessory App, and if they don't want its display taking over their screen every time a car approaches, then can opt for audio warnings only.

Like the Varia, the CarBack incorporates a tail light. In Trek's case, the company's existing Flare RT fills the role. Reportedly the "best in-class running light," it can be set to four different flashing/output modes, the brightest one pumping out 90 lumens.

Trek also claims that the CarBack has the longest detection range of any bike radar system, topping out at 240 meters (787 ft) as opposed to the Varia's 137 m (449 ft). It's additionally said to gauge distances more accurately, and to be the only system that indicates if cars are staying in their lane or pulling out to pass the cyclist.

The Trek CarBack's LED battery level display
Trek

The device itself is 70 mm tall, weighs 87 grams, and is IPX7 waterproof (meaning it can withstand being submerged down to 1 meter/3.3 ft for 30 minutes). One four-hour charge of its lithium-polymer battery should be good for seven hours of runtime – a four-bar LED on the side lets users check the charge level.

The Trek CarBack is available now via the company website, priced at US$199.99. It's demonstrated in the video below.

By way of comparison, Garmin's Varia RTL515 also costs $199.99, although the tail-lightless RVR315 model is currently going for just $99.99.

Source: Trek via BikeRadar

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7 comments
Trylon
Seems like they missed a perfectly good opportunity. If you have radar, there's no real need to have a constantly flashing light, which can be annoying to people around you. Just keep the light off until the radar senses an approaching car. If it's approaching slowly, it can flash at a closer distance, like 200 feet. If it's approaching rapidly, it can start flashing at longer distances proportional to the closing speed, and with a more aggressive flash pattern.
paul314
If it's true, that additional distance is a big deal. On some country roads, closing rates of 20m/sec are pretty common, so the transition from "Oh, there's a car behind me" to "Yikes!" is uncomfortably quick. But if the radar beam is narrow enough to supposedly detect when a car is pulling out to pass, I worry about how well the system will work on any road that isn't dead straight.
DaveWesely
Excellent suggestion Trylon. Plus, make a deluxe model with a camera for evidence against reckless drivers. It's already paired to a phone for data storage. Add an app based emergency alert in case of an accident.
BlueOak
@Trylon, disagree. Been riding seriously for several decades and prefer that drivers see me as early as reasonably possible. And suddenly activating a flashing light as the vehicle gets close could be more aggravating, even surprising them.
paul314
@BlueOak I agree there. Do not surprise the questionably-navigated multi-ton death machine. (As a driver, I sometime am troubled by certain cadences of blinking bicycle light, and the extra seconds of "what the heck is that" are not good. As with cars headlights and taillights, bike lights should be bright enough and with timing to be clearly visible, without being so bright or oddly paced as to be a distraction.)
Trylon
@BlueOak, so why don't cars have constantly flashing lights? Why aren't all warning lights constantly flashing on all devices? A light that's not flashing all the time gets more attention when it does start to flash compared with a constantly flashing light that gets pushed to the back of your mind. And I've been riding seriously for over four decades.
BlueOak
@Trylon, vehicles don’t have always flashing lights for two key reasons:

1) They are the predominant mobile objects on the road and their drivers expect to come across other similar speed, similar size, vehicles. Bicyclers are an exception, much smaller, traveling much slower, an exception just like a stranded vehicle on the side of the road… with its flashers blinking.

2) Power capacity on a bike is far more limited making vehicle sized running lights impractical. Smaller, but flashing lights overcome that shortcoming.