You don’t have to limit small blinking red and white lights to your Christmas tree during the short days this holiday season. You, or the cyclist in your life, can appreciate some bright options to decorate your bike and keep you visible and alive during evening rides. We’ve been testing two rear flashing lights from Serfas and Knog, and have been enjoying nearly eye-searing visibility from the Serfas Thunderbolt and Knog Blinder 4V.
Serfas Thunderbolt Bike Light
The Thunderbolt offers 35 lumens of bright red light from a 30 micro-LED strip. At full strength, the light lasts just 1.5 hours, but three other settings in a low beam (7 hours), high blink (3 hours) and a low blink mode (9.5 hour life). Charging takes six hours from a completely dead battery, and uses a mini-USB port, which is convenient in that you can use a cable so that the light doesn’t have to be sticking out from your laptop, but we’d rather see a micro-USB port since most popular smart phones have moved in that direction.
Silcone straps make it easy to mount the Serfas Thunderbolt tail light on a seatpost or seatstay in seconds, and because the straps are removable, you could lose them, but thankfully Serfas sells replacements. Our main complaint is that in the dark, it’s often hard to find the on/off switch. It’s on one side of the light under a Serfas logo, but seeing or feeling the switch in the dark is at best a 50/50 shot.
The Thunderbolt also comes in a 90 lumens headlight version, which is great for front visibility and shining a bit of light on the road or trail. It’s a bright, wide pattern, but be warned: if you mount it on your handlebar, the wide light pattern will catch your eye and can be distracting. A strategically placed piece of electrical tape can help shield your eyes from unwelcomed light. Seven color options.
MSRP: $45 (each)
Knog Blinder 4V Bike Light
The Knog Blinder 4V rear tail light offers a bit more light than the Serfas Thunderbolt at 44 lumens, with a more focused pattern coming from four large LEDs. The Blinder 4V has a lot going for it, with four flashing modes and one steady mode, giving anywhere from 3 to 50 hours of battery life and light. There’s even a storage mode for maximum battery life when not being used for extended periods. Our favorite feature is the built-in USB charging port that plugs directly into your laptop or charging cable — no little adapter or proprietary cable to find to charge the light. The downside with this is that you might need to prop your laptop up or re-arrange your configuration to make room for the light while charging. One silicone strap and clamp fits tubes from 22mm to 32mm in diameter, which includes most common seat post sizes. Six color options.