Helmet Mounted Rear View Mirror

A quick low cost solution for a horizontally wide angle view of what's coming up behind you. The total cost of parts not found around the home is $3.99 (for the mirror). Compare to an off the shelf rear view mirror starting at $14.99. Also, this mirror provides a wider horizontal view than the circular off the shelf mirrors!

Note that while specific materials are mentioned here, substitutes are readily applicable. For example, using Coat hanger wire instead of galvanized wire as well as using duct tape in instead of epoxy/SuperGlue. You don't even need to use the rectangular mirror. You can use the circular type or make a rectangular mirror from a circular one. in all cases, a convex mirror is most appropriate. Flat mirrors just don't have the coverage of a rectangular convex mirror.

Step 1: What You Need

You will need the following:
1. Special Mirror (see image and description below). Typically found at auto parts stores like AutoZone
2. About a foot of 14 gauge galvanized wire (or similar substitute like copper wire). I find aluminum and copper wire is not stiff enough. It seems to always get bent out of shape. Galvanized wire holds its' position very well. Wire from a coat hanger would probably work just as well!
3. An alligator clip (or other suitable substitute). Alligator clips with teeth work the best but they will mar a surface. Other "toothless" clips seem to always slip out of alignment.
4. Epoxy (or other suitable adhesive). Five minute epoxy seems to work best as it provides a bit of time to assure correct placement as well as provide a large adhesion area. Superglue tends to pop loose when twisted.
5. About a 3 inch by 2inch bit of strong self adhesive tape.

You'll note that other than the specialty mirror, everything else can be found around the house. The mirror itself can be cut out of a circular mirror. Why rectangular? Well it allows for a wider, single glance horizontal view of what's behind you while eliminating a lot of vertical view that is not needed in a circular mirror.

Step 2: Mirror Disassembly and Preparation

The first thing to do is remove the mirror from the plastic housing. You don't necessarily have to do this but I find it removes mass (bulk) which reduces the amount of weight hanging out there on the end of the wire.

After removing the mirror, I found the reflective coating exposed. I covered this with clear packing tape. The tape will provide a very good surface to glue the wire.

Step 3: Attaching the Wire to the Mirror

The back of the mirror will be concave so the straight part of the wire will be raised above the surface a bit. I slightly bent the wire so it would conform to this surface. This will reduce the amount of adhesive (and hence weight) than if the wire is raised above the surface.

I used 5 minute epoxy which has held very well. This might be bit of overkill but it sets and cures much faster than say an RTV solution. Super glue needs a lot of contact between the surface and the wire. It also breaks loose when side loads are applied to the wire or mirror.

Anyway, how you attach the mirror is not nearly as important as attaching it in the first place.

Step 4: Trial Fit

Once the glue has set you can now perform a trial fit to find out how long the wire needs to be.

To do this, put on your helmet and hold the mirror in a position that allows for unobstructed viewing to the front yet allows you to quickly shift focus to the scene behind you. My mirror is positioned 5 inches directly in front of my left eyebrow. The view places the juncture of my left shoulder and the left side of my face just at the lower right corner of the mirror. This provides maximal coverage to the rear. Turning my head very, very slightly in either direction significantly expands the area viewed.

Hold the wire on the helmet at the point where you will attach the mounting clip. At this stage you can start bending the wire for initial positioning.

Once you have found the best position, allow for about an extra inch and cut off the excess wire. This extra wire will allow for mounting to the alligator clip and provides a bit of slack for fine tuning.

Step 5: Attaching the Mounting Clip

I leave this step to the reader. An image of how I attached mine is provided (I crimped and glued).

If you used copper then soldering is a good alternative. Don't forget a heat sink to prevent excess heat from melting the mirror!

Step 6: Completed Assembly

This is how mine looks unmounted.

Step 7: Mounted Up and Ready to Ride

Here's a front and side view. Fine adjustments can be made especially when transferring from one helmet to another.

Total project time: 30 minutes.

Comments

[shalomfern]

BAD Idea! You can easily lose an eye in the event of an accident.

Do not attach those helmet mirrors. Your vision is impaired with them too. If you really want side mirrors get the ones that mount to the handlebar.

[gmartin2000]

I get your concern but I have had absolutely no cause for concern going on 20 years with one version or another. First, there are no sharp edges or pointy end of wires to damage ones' eye. The mirror is lightweight plastic, and the alligator clip has not sharp points or edges. I've dropped my helmet a number of times and the mirror always pops off (and it's never popped off the wire when using epoxy). That and we all wear some kind of eye protection when we ride don't we? ;)

And FWIW, I've lost or damage more than a few of these since I originally posted this. I haven't changed the basic design in all these years so the replacement cost winds up being the cost of the small mirrors. I'm still using wire from my first roll of 14awg galvanized wire. I used a coat hanger twice until I found my wire after a move. The coat hanger works just as good.

I suppose I should address the handlebar mounted mirrors too. I way prefer the helmet mount as the eye/focus shift is so much faster and easier than looking down to find the small mirror on the handlebars, then trying to focus and concentrate on the rear view while moving forward (I almost rear ended a car one time because it took me longer than expected to use the handlebar mounted mirror). Properly mounted, the helmet mirror does NOT obstruct the most important parts of the forward view because it's mounted UP above the horizontal. The fact that it's closer to the eye means you need a smaller mirror to see a very large area behind you. And small head movements show a vast amount of area behind me at a glance. I'm pretty much spoiled by the helmet mounted version which I feel is much safer and convenient than the alternative.

Oh yeah, one last thing, don't be tempted to use larger mirrors or flat mirrors and especially don't use glass ones. The small, plastic rectangular convex "Wide Field" mirror shown here is the best type I've ever found.

[devonfletch]

Bicycle spokes are a great resource, perfect for applications like this. They come in various lengths, and materials, (all pretty hard steel/alloy), and they've got a handy 'head' on one end, and a rather long thread and nut on the other. I use Stainless spokes for applications that are on view.

[Phil B]

My experience with a longer wire mount such as you have is that the mirror tends to shake up and down when riding, and that makes an accurate fix on my traffic situation difficult to get. The aligator clip is a clever way to attach to the helmet.

[gmartin2000]

Hi Phil: Another reason for the stiffer galvanized wire. You are correct about the vibration. I got that in the earlier, more bendable aluminum and copper wire versions. The 14 gauge galvanized wire (from places like hardware stores and WalMart) vibrates a whole lot less. Thanks for pointing this out!