Seven years ago, I rode my bike across the country with nothing but a $13 red bike light strapped to my seatpost. It wasn’t very bright and functioned more as hopeful optimism than a true safety device.
Now I’m pleased to see that daytime running lights for bikes are being taken more seriously. The Bontrager Flare R puts out 65 lumens in daytime random burst mode—an impressive level of brightness that completely outdid every other rear bike light on the last group ride I was on. Daytime steady mode is more modest 25 lumens. Night time output is 5 lumens in steady mode and 65 lumens in burst mode.
What’s a lumen? I read somewhere that lumens are to light the way gallons are to milk; it’s a measurement of how much light is given off. A standard 25 watt lightbulb (the ones that are difficult to find nowadays) gives off about 220 lumens. Car brake lights are around 350-500 lumens.
Anyway, Bontrager claims this light can be seen from 2 kilometers (1.2 miles) away during the day and 5 kilometers (3 miles) at night. I couldn’t find a stretch of road to test that, exactly, but I was able to find out that if you look directly into this light while standing next to your bike, it will mess up your vision for a few seconds. The Flare R also has decent side lights and claims 270 degrees of visibility. Its four modes are easy to toggle through via a large button on the top of the light. That same button features a status LED light that displays battery life.
The light easily unclips from the stretchy rubber seat post mount and charges using a micro USB cable (included). If the light gets down to 5 percent of life or less, it will need two hours to full charge. Thanks to not needing tools to mount this light, it only takes a few seconds to swap it to whatever bike you’re about to go ride and means there’s no reason not to. I’ve even stuck it on my mountain bike when riding from home to the trail.
Battery life is a claimed 5.75 hours in daytime flash, 23 hours in night time flash, 4.25 hours in daytime steady and 21 hours in night time steady. I left the light on in the house and hit those numbers almost exactly. When the battery dips below five percent of life, the light will automatically switch to flashing in a low-energy mode to conserve its life should you still be far from home.
When mounted using the bracket with rubber strap, the light swivels easily. It’s too small to fit around a large aero seat post (sorry, triathletes) and a bit too large for super-skinny road bike seat stays, if that’s where you’d rather mount it. But Bontrager includes a seat pack clip for the light, which is much appreciated by this short rider who often has no room left on a seatpost when a saddle bag is attached.
Finally, the Flare R is neither bulky nor heavy (36 grams), so weight weenies rejoice. At $60 it’s not cheap, but the construction feels hearty and has so far proven to be weather resistant. Bontrager says it focused on a daytime taillight because studies show that 80 percent of cycling accidents occur during the day. So even if you don’t get this rear red light, consider getting one.