Amber LED Tail Light Retrofit

Several years ago I decided to retrofit my red-LED Vistalite tail light with orange LEDs. It's attracted a lot of attention, so I decided to write it up. Please note that this article is from the mid-'90s and LEDs have made a lot of progress since then, so the part numbers given are out of date.


Amber light is more visible than red light to most people. In addition, some concern has been expressed that the nearly monochromatic deep-red light of most red LEDs is poorly perceived by some drivers with red/green color blindness. An obvious suggestion for cyclists with limited power supplies is to use amber blinking lights instead of red ones, since unlike motorists we do not have large alternators running off our engines.

A reasonable question, then, is legality -- are amber tail lights legal? The exact law varies by jurisdiction, but according to the King County, Washington Bicycling Guidemap's "10 Common Questions About Washington Bicycle Laws,"

5. Q. What equipment is required on bicycles used at night?
   A. A white front light and a red rear reflector are required
   (RCW 46.61.780). In addition, a red lamp and/or flashing amber
   light is allowed. Use of reflectors alone does not satisfy state
Check your own local laws before relying on this! Laws vary widely by state and country. Some states have now made blinking red lights legal on bicycles, others have not, and some may not allow amber blinking lights, either.


Amber covers for VistaLites are available -- any bike shop should be able to order them for you for a few dollars. In the U.S., if your shop claims they aren't available, ask them to look at the VistaLite parts in the United Bicycle Parts catalog, or buy them yourself from Loose Screws.

But changing the lens only changes the filtering and reflection of light, not the output of the LEDs. To fix that you need to replace the LEDs themselves.

I replaced two of the five red LEDs in my VistaLite with suprebright yellow LEDs, and many motorists have commented on the improved visibility. At a distance the red and yellow LEDs blend together to make a very bright amber light. Up close the yellow LEDs look a bit brighter than the red ones, but the combination still looks like an amber light to me. I haven't found a color blind person to ask about it yet.

Replacing the LEDs is very simple -- remove the screws holding the circuit board into the light, unsolder the LEDs you want to replace, and solder in the new ones. Be careful not to damage the traces on the circuit board by overheating them. LEDs are diodes, so you need to get the polarity right -- look for the flat edge on the bottom of the LED's case and align it with the other ones on the circuit board.

In case anyone else is interested, these are QT brand super bright T 1-3/4 yellow LEDs, clear lens, forward voltage 2.1 typ/2.8 max, peak wavelength 590 nm, viewing angle 20 degrees, luminous intensity 1600 min/2400 typ. They cost 82 cents each from Mouser Electronics, when I was making my light. The exact part number will no doubt change as technology progresses -- LEDs are getting brighter all the time.

This page written by Josh Putnam. Please feel free to email questions, comments, corrections, suggestions, etc.

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