Bontrager Flare RT rear light review

The Bontrager Flare RT rear light is compact, light and powerful

Cycling Weekly Verdict

A seriously advanced light in a seriously small package. Take the time to learn to use it properly and you'll be very impressed.

Reasons to buy
  • +

    Light weight

  • +

    A lot of technology

  • +

    Can turn of ambient light sensor as you wish

Reasons to avoid
  • -

    Mode settings can be a bit confusing

You can trust Cycling Weekly. Our team of experts put in hard miles testing cycling tech and will always share honest, unbiased advice to help you choose. Find out more about how we test.

Bontrager has, for a long time, made some seriously impressive bike lights, but now with the Bontrager Flare RT it has shrunken the design and increased the performance. The small unit is a treasure of smart technology, earning this little light a spot on our Editor's Choice list.

Despite its small size, the Bontrager Flare RT rear light manages to pack a punch thanks to the amount of technology packed inside the tiny unit.

For starters, the bike light has five different modes that riders can use, each one varying in intensity anywhere from 5, 25, 45 and 90 lumens.

At first, I found that the Bontrager Flare RT wasn't as bright as the old Bontrager Flare, a light I really rated. However, it turns out the Flare RT's in-built ambient light sensor was auto-adjusting the lumen output depending on my light conditions.

You can actually turn this feature off by holding the power button for 8 seconds when the light is turned off. The light will flash and when you turn it back on you'll find the old Flare's reassuringly bright output returned. I tend to only do this if I'm commuting home at night when I prefer the re-assuring brightness of the un-adjusted rear light – I like to think of it as turbo-charging the light.

However, if I'm riding in the daytime, I'm happy to let the light do its own thing. It's worth bearing in mind that the ambient sensor is also a battery saving feature and running the light full blast will drain it faster. A small flashing LED lets you know how much you have left.

Bontrager Flare RT

Small and compact light

It is possible to get a little lost in the array of modes, but you can 'lock' in the one you want, meaning next time you start up the light, the same mode is used automatically. Simply put the light in the desired mode and then hold the power button for eight seconds to lock it in.

The light also has smart connectivity to Garmin Edge devices, and I currently have mine setup so that it turns on or off when I turn my Garmin Edge 820 on or off. I also have a data screen showing the light's battery level.

I've found the Bontrager Flare RT to be a reliable winter bike light, riding through sopping wet roads and pouring rain has done nothing to dampen its spirits. The micro-usb charging flap is impressively well sealed, although it does sit on the bottom of the unit facing the wheel spray.

I'm also pleased to see that Bontrager has improved the light's mount which on the last Flare broke quite easily. Now the light comes with a sliding plate design and rubber strap, although it's better suited to standard seat posts over aero ones.

All of this inside a unit that weighs just 33g, strap and all. Pretty good going by our books.

Thank you for reading 20 articles this month* Join now for unlimited access

Enjoy your first month for just £1 / $1 / €1

*Read 5 free articles per month without a subscription

Join now for unlimited access

Try first month for just £1 / $1 / €1