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Cycling radar is an extremely popular accessory for road and gravel bikes. Over the last few years, many riders have started using on-bike radar systems to notify them of vehicles approaching from behind. Cycling brands like Garmin, Wahoo, Trek, and Lezyne sell radars that have performed well in our testing.
While many riders opt for a Garmin Varia RLT515, the radar we consider the segment’s benchmark, others ask, “What’s the cheapest one I can get?” It’s a question I often field from readers and friends wanting to purchase a radar device. Radar units aren’t super expensive in general (the priciest one is $400), but you can now find many budget-priced options on Amazon and AliExpress for as little as $20.
Pros
Highly reliable and consisent.Cons
USB-A charging.
And I get it; unless you’re a top professional, cycling gear isn’t free. Many riders aren’t ready to spend good money on something they’re unsure if they’ll actuall like. So, it can be tempting to buy a low-cost radar to try before splurging on a name-brand unit. But should you leave your safety up to a cheap radar?
Over the past year, Bicycling’s editors and test team have tried a dozen radar systems across the full range of prices. We urge caution when shopping for a cycling radar solely on price. While two low-cost radars performed well, four did not meet our expectations in ride testing on our local roads.
Radar Lights
It’s important to know the types of radar lights when shopping for a cheap radar. Read the product information carefully to ensure you’re buying what you expect.
When most cyclists and brands use the term “radar light,” it typically refers to taillights with integrated radar that provide the rider with an audible or visual warning to alert them of a vehicle approaching from behind. These are the types of radar lights our editors test and use.
However, some cheap radar lights only use radar to brighten the taillight when a vehicle is detected. These lights do not provide the rider with any warning or notification about an approaching vehicle. Be aware of these lights when shopping.
A good way to tell if a radar light will alert you about approaching vehicles is to check the product specifications. Brands will usually note Bluetooth or ANT+ compatibility (and a list of compatible head units) along with photos of warnings on a cycling computer or mobile app.
trevor raab
The Magene L508 is a radar we like for less than $100.
What Makes a Radar Good?
One trait defines the radars we like from the ones we avoid: Trust.
Since you’re putting your life in the hands of a radar when you’re riding, it must reliably and dependably do its job. The best radar systems consistently provide ample warning of vehicles and seamlessly blend into your ride because you trust them so much. But even good radars should consistently provide you with warnings of approaching vehicles and give you sufficient time to react.
As the manufacturers admit, no radar system is perfect. False positives—the radar detects something and alerts the rider, but no vehicle is present—occur with every unit. Sometimes called “ghost cars,” false positives can be triggered by various things in the riding environment. Reflections in windows, trees, dogs, and chainlink fences are some common culprits. While a little annoying, a ghost car doesn’t result in disaster for the rider.
False negatives, by contrast, can result in serious injury or death for cyclists. This happens when the radar unit fails to detect a vehicle approaching you from behind, or the radar doesn’t notify you at all. Good radar units seldom, if ever, produce an outright false-negative.
Radars that make you look over your shoulder constantly due to repeated false positives erode your trust in them. Even worse are systems that consistently notify you too late of vehicles or regularly miss vehicles entirely.
When this happens consistently, you stop paying attention to it or shut the device off. At this point, the radar unit effectively becomes nothing more than a heavy blinky light with shorter battery life. By definition, these are not good cycling radars.
An example of a good radar is Garmin’s RTL515. This is our benchmark radar taillight for both performance and price. It tracks vehicles well, has good range, and rarely gives us ghost cars. The device has been around for years, yet it still outperforms most competitors.
Radars to Avoid
Of the dozen radars we tested over the last year, the median price is $154.99. So, let’s consider any units costing less than $150 as “low cost” options—We tested six of them. There are a couple of good radars available in this price range, and there are some stinkers.
The four we cannot currently recommend are iGPSport ($79.90), Cycplus ($89.00), Ravemen ($99.95), and MagicShine ($129.99). Each device proved unreliable in ride testing. All of these units suffered from so many false positives that we could not trust them on rides.
These false positives distracted us from riding, and we found ourselves constantly looking over our shoulders to see whether the alerts we received were valid threats or ghost cars. Additionally, these units did not reliably track targets, either notifying us too late to move over or giving us an all-clear when a vehicle was still present.
I found MagicShine’s SeeMee R300 particularly egregious. It notified me of ghost cars with such persistance that I remarked in my notes after the first test ride, “This thing isn’t a radar light, it’s a gaslight.” On my second try with the unit, it produced even more false positives; I shut it off to maintain my sanity.
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Bryton’s Gardia R300L is another low-cost unit we like.
Good Low-Cost Radars
While four radars did not meet our expectations in testing, two low-priced options—Magene and Bryton—held their own against some of the big brands.
The Magene L508 ($99.99) and Bryton Gardia R300L ($129.95) radars tracked vehicles, provided sufficient warning, and had decent battery life. Plus, they both have USB-C charging and an integrated brake light—features which Garmin only recently introduced on its premium-priced Varia RearVue 820 radar.
The Bryton and Magene devices are examples of lower-cost options that work well. While we experienced some ghost cars on rides with both radar units, the false positives weren’t excessive.
I lent the Bryton Gardia to a friend for a 25-mile ride last weekend, and I used the Garmin RearVue. Riding side-by-side, the RearVue detected cars from a further distance. However, the Gardia still gave us ample warning of approaching vehicles and rarely experienced ghost cars.
The Magene performed similarly to the Bryton in my ride testing. It gave me some false positives, but they were not excessive. The L508 also has a nice form factor and programmable flash settings.
Bottom line: Whether you’re buying the ones we tested or another option, do your homework before purchasing a cheap radar. Dig into the details, read/watch third-party reviews (such as Shane Miller/GPLama), and talk to actual users to learn about their real-world experiences. And when the highly reliable Garmin Varia RTL515 is available for $150, is it worth the headaches and safety to save only (at most) 70 bucks?
Benchmark Cycling Radar
Garmin Varia RTL515
Now 25% Off
A Solid Radar Option
Our Lowest-Priced Pick
Can the Others Improve?
As Magene and Bryton show, lower-priced radars can perform reasonably well and be trusted by users. However, both brands went through teething pains and firmware updates until their devices reached this level. Unfortunately, some early users of these systems essentially field-tested the radars.
But that means there’s hope that MagicShine, Racemen, Cycplus, and iGPSport’s units can be improved. Perhaps these brands can modify their firmware and push updates to decrease the false positives and make their devices more reliable. Currently, these systems are not up to snuff, and there are many reliable options available for not that much more money.
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As Deputy Editor, Tara Seplavy leads Bicycling’s product test team; after having previously led product development and sourcing for multiple bike brands, run World Championship winning mountain bike teams, wrenched at renowned bicycle shops in Brooklyn, raced everything from criteriums to downhill, and ridden bikes on six different continents (landing herself in hospital emergency rooms in four countries and counting). Based in Easton, Pennsylvania, Tara spends tons of time on the road and trail testing products. A familiar face at cyclocross races, crits, and bike parks in the Mid Atlantic and New England, on weekends she can often be found racing for the New York City-based CRCA/KruisCX team. When not riding a bike, or talking about them, Tara listens to a lot of ska, punk, and emo music, and consumes too much social media.