Motorcycle LED Brake Light

Editor's Note:  The subject of auxiliary and LED brake lights has been a very popular topic with webBikeWorld visitors for many years. 

We started reporting on LED lights before they were being used on motorcycles, back when LEDs were rare, expensive and not very bright -- and when most of the LED lights that were available had to be specially adapted for motorcycle use.

LEDs have evolved quite a bit since then and the prices have dropped to a point where it is not uncommon to find them installed as original equipment on many different vehicles, including large trucks and trailers.

Based on what I see on the road, LED brake and tail lights seem to have overtaken their incandescent forebears as original equipment on the big rigs (although we don't have any data on this). 

Those truck LEDs are big, bright and bold, in case you haven't noticed, and we've often wondered how they would work -- and look -- on the back of a motorcycle. 

So this article by author David G. sort of brings us full circle to yet another LED experiment; this time it's adapting a truck LED light for motorcycle use.  David found a good deal on a couple of big, honkin' LED truck lights and he wired 'em up to see what happens.  This is his report.

Supplemental brake lamps, a.k.a. "third brake lights", are a continuing item of interest among motorcyclists.  Granted, the most important improvement one can probably make is to install supplemental driving lights or a headlight modulator to increase the motorcycle's visibility to oncoming traffic, but brake lights seem to hold more interest with bikers.

This is curious, because, according to statistics, fatalities from rear strikes are a fraction of frontal crashes (although there is no data on non-fatal rear-enders).  Even so, it pays to ensure following drivers notice you, especially when slowing for a turn or when coming to a stop.

My interest in rear-end visibility peaked after a scary highway near-miss.  The sound of skidding tires and the image of an SUV growing larger and larger in my mirrors was a real attention-getter, I can tell you.  Fortunately, the wannabe assassin stopped short with about a meter to spare.  As a result, one thing I have done is to adopt my motorcycle instructor’s favorite quote relating to why one should invest in high-quality safety equipment:  “It’s cheaper than skin grafts or a body cast.”

By way of background, I live in a rural area on the scenic North Oregon Coast of the U.S., and we get more than a million visitor vehicles each year.  These tourons -- i.e., "tourist-morons" -- frequently spend more time scoping out scenic vistas or looking for a place to pee than watching the road.

And because we're a retirement destination, we also have a large population of elderly residents.  It is not unusual to see a car piloted by a shrunken, snowy-haired person of indiscernible gender who is barely able to see over the dash.  The point is that city or country, we all face multiple threats from inattentive, impaired and distracted drivers, so anything you can do to make you and your motorcycle visually evident is a smart move.

After my little scare I dutifully read all of the webBikeWorld and other articles on after-market brake lighting, which gave me some great information on the advantages of LEDs.  Several reviews and web crawls later, I came away wondering if the small LED assemblies marketed as "third brake lights" really have enough horsepower for the twin threats of blind geezers and oblivious tourons.  It is hard to imagine that a few tiny lamps are effective at 100 feet or more...

In addition, a recent headlight experience has colored my thinking about the role of size in lighting.  A friend recently installed a pair of 2-1/2 inch, 55 watt halogen driving lights with round projector lenses on his motorcycle.  But during daylight hours and from a distance, I discovered that they appear only marginally better than the stock amber turn/running lights. 

So with that in mind, I outdid him by opting for a pair of 3-1/2” by 5” off-road reflective lamps for my bike.  With identical 55 watt bulbs, the reflectors provide a two- to three-time larger "optical footprint" for oncoming drivers.  The moral of the story? "Size matters".

I decided to also apply that lesson to the rear of the bike, and I supplemented my stock brake light with something in between the tiny little munchkin lights and those big, ugly units you see on trucks and buses.  But, as I discovered, most of the industrial-grade LED assemblies I found were either round or oval, and nearly all require flush mounting. 

I was just about to give up the notion of an acceptable solution when the “6-Inch SuperBrite Red LED” marker light shown here caught my attention.  These sealed, ultra-bright, vibration resistant, surface-mount units feature 21 LEDs per unit with each bulb sporting its own personal reflector.  At the time this article was written, they were on sale for $15 each, a great price for what you get.

When the lights arrived, I attached one to a battery to check out brightness.  The resulting painful blast of red was surprising – and just what the doctor ordered!

In comparison to other auxiliary brake lights, the 6-Inch SuperBrite Red LEDs are quite large and about the size of a stock motorcycle brake light lens.  Since you can’t be too rich, too famous or have too much visibility in traffic, I opted to use two of these suckers. 

The combination of their size, their wire leads (rather than a protruding plug) and their surface mount design provide natural location flexibility, such as:

• License Plate:  A single LED light mounted above or below the tag effectively doubles your brake light transmission.  Two units, for a total of 42 LEDs, on opposing sides of the plate was my preference.

• Saddlebags:  Vertically or horizontally mounted lights on rear panels.  Soft bags may need an internal stiffener.  Slant or angled bags won’t work without a wedge shim to make the light vertical - you’ll see why below.  Most owners, however, won’t be interested in putting screw and wire holes in pricey luggage.

These are not those wide-broadcast LED units with a premium price tag; rather, maximum light is spread in a 21-degree "cone of light" (see illustration below). 

Outside of this area, to about 45 degrees per side or 90 degrees total, the lamps and reflectors deliver light at about the level of a regular tail light – still visible but lacking that desirable, eyeball-frying intensity.  However, I found this performance issue to be a minor downside when compared to the multiple advantages of these lights.

The LED "Cone of Light"

By positioning the units so they're pointed slightly upwards, drivers in close-following RVs and commercial trucks will get their fair share of red light.  In a darkened garage, the intense central cone of illumination projects very crisply on a wall or closed door.

Shim the light mount so bottom edge of the "cone of light" is broadcast at the same height as your tail light.  You could also point a pair slightly outboard, retaining a 10 degree overlap, to push effective cone width to 30 degrees.

One final installation tip:  The license mount on my Honda 600 VLX and many other motorcycles is a flimsy, molded plastic assembly, so a lightweight mounting plate was needed.

A visit to my local sign shop yielded a thin, feather-light, rigid, double aluminum sheet laminate over a plastic core.  There are two brands -- U.S. made Dibond, generally available in white only, and British made Alupanel which has a full spectrum of colors to pick from including chrome.

Alupanel sheets have matching color on both surfaces, one side is matte and the other is gloss.  There is usually scrap material available for next to nothing, check with an area sign person for availability and color selection.

Automotive flash modules can be utilized; see the Miata.net site for a good set of instructions.  Incandescent flashers may require a resistor addition for LEDs. 

Other LED specific circuits allow you to program flashes, timing and full-ON sequences.  Talented do-it-yourself types can even obtain a schematic for a user-adjustable module.   I added a $20 "flash-flash-on" circuit found on eBay.

Where to Buy the Flasher
Q. "I’m writing regarding David G’s article on the 6” LED truck lights.  I’ve been looking all over eBay trying to find the flash, flash, on circuit he mentions but have had no luck.  Can you please suggest a manufacturer or other source for these? I already ordered the lights."

A.  The current offering from Rearalert is actually cheaper and appears to be almost the same - search on "brake flasher".  It is probably based on the same #555 integrated circuit as are similar units but the "de-acceleration" term is misleading.  My definition of "de-accelerator" sensor involves a stress triggered switch or strain gauge to power a light without touching the brake which is not what they describe in the text of this unit.

The only apparent difference is that mine has a trimmer/rheostat (versus wire jumper) built into it so you turn a screw to shorten/lengthen flashing.  I also opted to branch off the brake wire so the main light remains solid at all times.  The flashers are sometimes for sale on eBay; check item #  110216438772 or Electro Flasher. 

Finally, given the plethora of flashers out there with price points ranging from $16 to $50, a review of flasher approaches might be a good future project for someone.

Summary
The 6" SuperBrite LED Truck Lights function perfectly as a "third brake" light for motorcycles.  For urban and freeway environs, with their multiple driver distractions and sensory competitions, I view supplemental brake lights with flashers as a "must have" safety investment.  I expect these lights to go a long way toward keeping my ass out of a sling - literally.