Garmin Varia RTL515 – a review

Despite various attempts at different types of riding, I’m sure that I’m a roadie at heart. 99% of my riding is on the asphalt, and I love it. There is however a tiny problem. In most places I’ve ridden, separated bike routes are a rarity, if not a luxury – which means that I have to share the road with motorbikes, cars, buses and trucks.

To be fair, most drivers are nice enough and give me a wide berth when overtaking, or even wait behind me until its safe to overtake. It however just takes one driver (regardless if aggressive or distracted) to make my day a nightmare.

Over the last few years of cycling, I have suffered enough drivers overtaking me with 10 cm clearance, those who tailgate me with a meter clearance at 60 km/h, and those who have simply tried to bully me off the road. Clearly, by virtue of my hobby, my life is of limited relevance to some.

One event in particular scared me so much that really I had to do something. Let’s be honest, nothing will change how these people act, however anything which gives me advance warning is extremely valuable to me.

Disclosure: I am not sponsored by Garmin and have paid for the Varia RTL515 in full with my own money. The below is purely my unbiased opinion based on my experience.

The Varia is quite large compared to some bike lights (about 10 cm long, 2.5 cm wide), with the red light at the top (including side windows) and the radar panel at the bottom. It charges using a microUSB plug and clamps onto the frame with a Garmin mount.


The Garmin Varia costs about EUR 200. Very expensive for a tail light. But it’s so much more. The Varia is both a tail light and a radar. It can detect anything coming from behind you (really, anything between a bicycle and a train) and it will do two things:

  • If connected to a compatible bike computer (including Garmins, Wahoos, and Hammerheads), a visual and audio warning will pop up. You’ll see how far the object is behind you (up to about 150 metres) and its relative speed. My Hammerhead shows yellow for moderate speed, and red for high speed.
  • Even if not connected to a bike computer, the Varia’s red light will start to flash as a car gets closer to you. There are four red light modes (including resting and flashing), but in any case the light will start flashing at a different frequency, designed to get the driver’s attention.
Here you can see the radar function pop up on my Hammerhead Karoo 2. The traffic didn’t come from far away, otherwise the car icon would start at the bottom of the screen (reflecting about 150m). You can also see the icons pop up for several cars in a row. Due to their relatively low speed the bar is yellow – if they are much faster the bar is red.

It’s really worth noting that my model is the RTL515. The RTL516 is another version designed specifically German users (in compliance with the StVZO law). In Germany, tail lights on bicycles must be solid and cannot flash.

If you have a choice, this restriction robs you of a vital safety function. From experience, the automatic flashing function makes a crucial difference to being seen and getting drivers to pay attention to you – if you can, go for the RTL515.

A new version of the Varia has just been released, which also includes a rear facing camera (external review here). This takes video on loop, and if the Varia detects that you have been in a crash, it will save the footage as evidence. I like the idea, but from my crashes so far, I have never been hit from behind. Based on reviews I’ve read, the resolution isn’t supposed to be great and using the camera will shorten the battery life. I’m not convinced of the benefits though, and even now I would still go for the older RTL515.

The Varia mounts to the seatpost, which is normally held by a rubber band. To dissuade casual thieves, I’ve mounted it using two cable ties.

The battery life of the Varia RTL515 is pretty good, giving me about a day’s worth of riding when in flashing mode. The power of the light is also pretty good (even during the day), making me nice and visible. It’s also waterproof, and has regularly taken a good drenching from my back wheel in the rain and in dirt – it still picks up cars behind me.

What’s really handy is that if you don’t have a dedicated bike computer, such as in the case of many commuters, you can also use the Garmin Varia app on your smartphone. I haven’t tried it myself, but it should show up any cars coming up behind you on the entire screen and give you audio warnings – the Garmin website shows more details on how it works. This means the Varia isn’t just for racers, but anyone on any bike.

Why not use a mirror, you might ask? I don’t really like the design of most mirrors, and the others are quite small and don’t give much detail. You also have to frequently look at the mirror, which is sometimes difficult if you’re riding a tough stretch of road. The Varia gives you audio warnings and shows traffic much further away – it really is system you can switch on and forget about.

I still look around me though. When I see a car come up behind me, I keep an eye on my bike computer to see where and how fast it is approaching. Depending on where I’m riding, I wait until the icon reaches a certain point (about 25m away) and look around to show the driver that I’ve recognised them and see how they act. I can then decide on how to respond.

The result

Hand on heart, this is truly a gadget that I cannot ride without, and I use it on all of my bikes (racing, touring, MTB, city). In a change to my usual “3 things I like, 3 things I don’t like” reviewing style, my rating is an “A+”. If you ride in traffic at all and don’t have one yet, please consider it, it really is a life saver.

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