The radar function works well, no false negatives but plenty of false positives. You shouldn't depend on it as your only warning for traffic coming from the rear, a mirror, your ears, and turning your head around every now and then is good practice. While the range meets it's spec, where I ride cars and pick-ups frequently pass you at 70+ mph on two lane country roads, with this (or any) radar that is only about 3 seconds. I can usually hear the car and see them in my mirror before the radar gives a warning. Still it's great to have when your attention wanders. The included mounts should fit most seatposts whether they're round or aero. My on demerit is the battery life, about 7.5 hours. I frequently ride 100 mile+ rides and the radar dies before the end. Also the charge port is a micro USB not the more common USB-C, I'd like to see that updated along with the battery life.

I debated for a long time about buying a Varia. I was getting a bit tired of all the accessories on my bike. But when this one went on sale, I jumped. It was very easy to set up with my Garmin and works well. I have issues with turning my head and haven't found a rearview mirror I like, so this makes me feel safer. I chose the Varia without the light because I was afraid the larger version wouldn't fit on my seat post under Cannondale's built-in light.

Le radar nous averti quand il y a un véhicule en approche et aussi quand il n'y a plus de véhicule. Sur l'écran on peut voir le nombre de véhicules derrière, au moins jusqu'à cinq et on est averti plusieurs secondes avant.

I have lots of rear red led even on my helmet , so the fact that this is minus a tail light does not bother me . that said I will never cycle without this unit. Information is power . this lets you know what is behind you .I still use my mirror and shoulder check as my primary info . but this adds the extra touch from way further back . I love it . must get one.

Peace of mind with it comes to safety. I don’t need to look back every 30s. Alerts whenever a vehicle or fellow faster rider is approaching and alert varies on the relative speed of the vehicle.Seamlessly integrates with garmin head unit and beeps when a car is on your back.Battery life is good enough for a few 50 km rides.

I had to mount it on the back of my seat stay because there is just not a good place on my rear rack. I was worried that it would affect the sensitivity. Nope, I am glad to say. Works like a charm. It actually very discreet down there.I feel a lot safer with this product. It makes me aware of encroaching cars sooner than I would otherwise. The app is straightforward and simple. 10/10

Have used this item for a few months and it works great when paired to the Garmin 1040 bike computer. It provides audible and visual alerts when traffic is approaching from the rear. A must-have safety device for those who ride on streets, roads and highways.

This thing is great! I have complete visibility to cars behind me without having to constantly look over my shoulder or try to keep a mirror adjusted. It spots cars further back than any manual method and can track multiple vehicles at one time. All right on your computer. I’ve never had a false positive or negative. Fantastic product.

Combined with my Edge 1030 this is a must have. Really increased my comfort road riding. 3rd party Connect IQ fields really make this device useful giving relative and absolute approaching vehicle speeds.

Absolutely amazing technology. Makes my small town fitness riding (I’m 65) much more relaxing and increases safety. Per the picture above, I have a ‘comfort bike’ (Trek Verve) with a very short seat stem and an aftermarket wide seat without the traditional brackets underneath the seat. So, problematic mounting situation. I used an aftermarket stem mount, and bought the 315 model, which is quite small without the tail light. I mount it upside down and have plenty of room between it and the top of the tire. Works perfectlyThis is a game changer for me. Identifies vehicles long before I could hear them, and provides great visuals on my Garmin130+ regarding speed and closing distance. The chime to signal initial acquisition of the vehicle is easy to hear. Perfect!Pairing and initial setup was very easy. A+ system for safe riding

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The Varia model tested was the RVR315 without the taillight (with the light it’s model RTL515).First of all, it’s a solid Garmin product. It is supplied with 3 seat post profile inserts and two sizes of O-rings to fasten the unit to the bike seat post. A micro USB cord is supplied for connection to a power source (not supplied). The charging port is protected by a well -designed cover but care should be taken when inserting the USB plug. As with all USB sockets, the unit can be damaged if the plug is inserted incorrectly or with excessive force. Battery life seems to be 3-4 hours. Battery is also reported on the Varia App screen. The RVR315 was tested with an iPhone 7 using the Garmin Varia App and the RidewithGPS App. The unit easily paired with both apps and will alert you if pairing fails during a ride.The radar will detect multiple cars behind you at up to153 yards as claimed. The unit does not report “all clear” unit the last car detected has passed you (great when you can’t see them all). However when you turn onto a side street and a car turns with you, the detection may be mixed. When riding straight and a car turns out of a side street behind you, the Varia takes a moment to detect the vehicle and it may not be detected until it is right on top of you. Overall the performance is quite impressive, it picks up vehicles at a distance and will alert you well before you can hear a vehicle approaching.VARIA AppThe app is streamlined with options to select some sounds/vibrations on the interface. The app displays a high contrast track on the phone that is readable even in bright daylight. Be aware the app does not sleep so the screen is using more battery time. Audio signal volume is moderate but adequate.RIDEwithGPS AppAfter pairing with the app, RwGPS adds a graphic track to the left/right side of the screen (your choice). It displays well, but the track is not displayed as well as the VARIA app. Also the RwGPS screen may enter sleep mode if selected and you lose the visual display, but the audible alerts will still be heard.Bluetooth Audio with Both AppsIt is possible to pair an external Bluetooth speaker with the app/phone to increase the audible announcements, but the results may be mixed with the external Bluetooth unit. An older Bluetooth 3.0 speaker did not report all of the expected tones all of time. Some alerts remain silent even as the phone app showed an approaching vehicle. When a Bluetooth 5.0 speaker was paired, the unit reported the audible alerts consistently. One curious note is that depending on the app or the external speaker the audible alerts may be slightly different tones.City riding with the Varia may yield some spurious results but it still quite good. Out on the longer stretches it is very consistent. In both scenarios it adds a safety factor that is hard to beat for any serious cyclist.