If you want a low-profile, fit-and-forget light for your road bike then the Topeak Redlite Aero is a good choice. Its output won't be melting any eyeballs but it's simple to fit in a variety of positions with a good field of vision.
The Redlite Aero couldn't be simpler really. Crack it open to put in a single AAA battery and turn it on, and the three LEDs will flash in the single blinking mode for a claimed 80 hours, or run constantly for 40. Mounting is a simple rubber strap with a loop at each end, which locates on a mount either side of the light; the rubber foot keeps it from moving about.
Two mounts are included, one that's designed to go around a seatstay and one for a seatpost. The LEDs are angled so that they're pointing about straight in either position, depending on which way up you put it.
It's not the brightest light out there by some margin, but it's plenty bright enough to be used as a standalone rear light on your bike, and the LEDs have a very wide field of vision thanks to the design, so there's plenty of visibility from the sides. The mounting means that the light hardly protrudes at all from the sides of a seatpost, which will be good news if you find your thighs clipping bigger clamps. And if it's still an issue you can bung it on the stay instead.
Topeak classify the Redlite Aero as water resistant rather than fully waterproof. The clip-together design suggests you might be able to force some water in on a really filthy ride, but I've not had any water get in during testing. The way it's designed means the mounting strap pulls the light down onto its rubber foot, creating a tight seal.
Overall it's a very likeable light. The simple design makes it a breeze to fit, it's bright enough to be used on its own, and the versatile mount means you'll easily find a place for it somewhere on the back of your bike. And is it aero, like the name suggests? Well, yes, I guess, although if you're worried about how aero your rear light is then you probably want to take a look at yourself.
Cleverly designed, unobtrusive rear light that's simple to fit, and easy to see.
road.cc test report
Make and model: Topeak RedLite Aero rear light
Size tested: n/a
Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Slim, aerodynamic tail light fits seatpost or seatstay perfectly. Rubber strap allows tool-free mounting/ removal and multi mounting positions.
Tell us some more about the technical aspects of the light?
Lamp 3 Super Bright Red LED's
Battery AAA x1 (included)
Control 2 Modes, Constant/Blinking
Burn Time (approx) 40 hrs / 80 hrs
Light Output 20 cd
Lamp Housing Injection Molded Plastic
Mount Fits Seatpost and Seatstay (ø25.4-ø 34.9mm)
Size (L x W x H) 6.6 x 2.4 x 3.4 cm
2.6' x 0.9' x 1.3' (light)
Weight 32 g / 1.13 oz
Tell us how the light performed overall when used for its designed purpose
Very well, simple to fit and works well.
Tell us what you particularly liked about the light
simple unobtrusive mounting and wide field of vision.
Tell us what you particularly disliked about the light
Did you enjoy using the light? Yes.
Would you consider buying the light? Yes.
Would you recommend the light to a friend? Yes.
About the tester
Age: 40 Height: 190cm Weight: 102kg
I usually ride: whatever I'm testing... My best bike is: Genesis Equilibrium with SRAM Apex
I've been riding for: 10-20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: commuting, sportives, general fitness riding, fixed/singlespeed, mtb, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.