Bike Helmet Rear-view Mirror

Anyone who has ever ridden a bike on a road with cars on it, knows why a rear-view mirror is a good idea: when you’ve got to see behind you and you peek over your shoulder, it’s hard to avoid swerving a little. A mirror can give you that much-needed glimpse of the road behind you, sans swerviness.

I didn’t want a handlebar-mounted mirror, because they have to stick out to the side quite a lot, have to be big enough to see, and are subject to theft. I didn't want to spend a fortune on a rear-mounted camera with a bulky screen mounted to the handlebars (also highly likely to "go missing"). I didn’t want to add steps to my pre-ride routine like having to fumble with the kind of mirror that clips to your sunglasses (although I find these bottle cap mirrors to be pretty badass). I was on the verge of buying one that sticks to your helmet and places a small mirror a few inches away from your face on a little wire, despite their disadvantages: many of the reviews on many of the models were complaining about low-quality mounting hardware, and how the mirror blocks too much of the user’s view.

[Full disclosure/Nerd alert: I briefly toyed with the idea of upcycling an old digital camera; mounting the screen up front, the lens on the helmet's back, and an easy-to-reach switch to activate when rear-view was needed, and hopefully not a lot of extraneous parts. It started sounding like fun, lots of little problems to solve… but then a little voice in my head whispered, “Dude, just use a friggin’ mirror.” So I’m like “Hey shut up little voice, I don’t need this kind of negativity in my life!!” But then I realized the little voice was likely saving me from a time sink of unfathomable proportions, and decided to keep it simple. That said, maybe a motorcycle helmet nerd could use that old-camera idea? Anyway I guess I owe the little voice an apology, but I'm still kind of mad so I'll do it later.]

In the end I settled on a version that's very similar to one made by David Taylor, and I like it for all the reasons David Taylor likes it.

The end result Is unobtrusive and works great, well worth the investment of ten minutes and zero dollars. It's low-profile, permanent (so I don't have to remember to clip it on), unlikely to bend or break when bumped, and as a bonus: it looks only marginally dumb.

I used the left lens from a broken pair of sunglasses, a tiny mirror I found in the junk drawer (originally from a craft store I think), some hot glue and a little black paint.

The mirror I had on hand was square, but I suppose a round one could work too.

The first image shows what we're shooting for from below: the mirror securely glued at the appropriate angle to see over your left shoulder, and the lens hiding the ugly glue job.

You'll of course need to make adjustments depending on your helmet's design, but for mine it made sense to stick the mirror directly to the exposed styrofoam.

Note: If your glue gun has a temperature setting, set it to "low" to avoid the possibility of melting your foam (and burning yourself)!

Another note: When I first upgraded to a new glue gun, I used to go with the high temperature by default. I found that more often than not the glue would flow too quickly, wouldn't stay put as well, and I'd end up with more "spider web" mess, plus a few micro-burns on almost every use! So low is now my default temperature, and I only crank it up when there's a really good reason to do so.

I put one small dab of hot glue behind the mirror and put on my helmet while holding the mirror in place, adjusting the placement and angle as the glue cooled. It ended up being pretty much perpendicular to the helmet's bottom edge, and to my left eyeball. I aimed the mirror so I can see only a little bit of my own big fat head, and have a good view over my shoulder.

Once the mirror is in the right place it can be reinforced with more glue so it stops wiggling, but the real strength will happen in step two.

I glued the lens to the front of the helmet, lining the bottom of the lens with the bottom of the mirror, then added more glue into the void between the mirror and the lens. On low heat, build up the hot glue in layers, allowing a little cooling time in between, until you feel like you've built up enough mass for stability.

The lens is mainly a cosmetic addition, though I suppose you could make an insufferable aerodynamic argument if you were so inclined.

Hot glue globs are ugly, but they practically disappear when you add a little black paint.

If I were more patient and focused, I'd fill the gap completely with hot glue and smooth it all out with a razor for a nice, clean, machined look, but I'm just not very HEY LOOK, A SQUIRREL!

A helmet-mounted mirror on a wire would have forced me to rethink where I keep my helmet when I'm not riding, but the profile on this setup is low enough that I can still store my helmet in its customary location: the five-gallon bucket stuck to the back of my bike (which looks dumb but works great, by the way).

This thing works great, and I'll definitely do it again if and when I replace my helmet.

Thanks for reading!