Topic: White vs coloured LED bulbs

[Mr.D]

I've been reading a lot on the forum about LEDs and have learned a lot. But I haven't read anything about this particular question I have so here goes:

Many people are suggesting using coloured LEDs (blue, red, green, etc) to replace the incandescent dummy lights but I'm wondering why I couldn't just buy regular white LEDs since the plastic lens of the dummy light is already coloured? The old incandescent bulb gives off white light, so why not replace it with something that gives off white light? Is there something I'm not thinking of? Do coloured LEDs look better? Brighter? Different somehow?

Same question with the tail light. People are suggesting using the red LED for the tail light, but that creates the problem of a red light shining on the license plate. Any reason why I can't just replace the incandescent bulb with a white LED? Will it not look right when it shines through the red plastic?

 

[SOHC4 Cafe Racer Fan]

I don't see why not.

[flybox1]

match the LED color to the color of the crystal or cover so you get the most light transmitting through.

[CycleRanger]

You can use white bulbs for the gauges but after 35+ years the colored plastic lenses on the panel have probably faded a bit.
I used colored LEDS for the  panel, they cost the same as plain white and I was happy with the colors being very colored! 
 (90 degree colored for the indicator bulbs and 120 degree white for the gauge lights)
As far as taillight, yeah I'd use white.

[Bodi]

The final colour light you want might not be so great with a white LED filtered through a lens. White LEDs are actually a blue LED coated with a yellow phosphor, some blue light goes right through the phosphor coating. The "white" light spectrum has a broad yellow hump and a blue line, the colour temperature is adjusted by letting less or more blue light through.
You will be wasting a lot of light by filtering it, for sure. Since you have a choice, use the same colour LED as your lens.
The original filament lamps didn't have any choice, they came in white light only.
If you want a blue LED note that they always seem to look twice as bright as the equivalent green, yellow, or red ones. I used blue for a high beam indicator and it was very bright and distracting at night.

[Bankerdanny]

You can.

However, as I understand the physics, the reason that Superbrite recommends bulbs the same color as the lens is because "white" light is actually made up of multiple colors each with a different wavelength, that's why when you shine light through a prism you get a rainbow effect.

A colored lens filters out the other wavelengths (colors) and the result is somewhat less bright than the clear bulb. A colored LED generates only the wave matching the particular color, so more light passes through the lens, creating a brighter light.

[Mr.D]

Thanks all for the physics lesson! I went ahead and ordered coloured ones. Except for the tail light, I decided to try the "Natural White", which at least won't be as bad as the "Cool White"... will see how it shines through the red plastic and let you know how it looks.

[Deltarider]

Personally I was never tempted to replace these existing bulbs by leds. Not much to gain, is it? I believe in all these years I've had to replace only one. I carry a spare bulb in the rubber spare fuse holder. All this work and costs for what?

[PeWe]

I replaced the rear 5/21w bulb with LED. I tried white and red both 12 and 24 LED version and all were crap. The std bulb is way better. Visibility with light on and when braking.
I think the bulb I specified 21W/5W the braking power first .
I use H4 LED for front which is an aprovement.
Bike is CB750K6


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[Bodi]

OK, hefty cost for little gain... but I tried several LED tail/brake lamps. Evrything I found at audo stores was total crap, dangerously dim brake light, invisible on a sunny day.
I got a high wattage one from superbrightleds. It has a single red LED chip on the end of the plug-in base. Wow! brighter than the usual 1157 replacement lamps.
I don't know what they sell now, I'm happy with this one. I think it's 3W at stoplight power, much less for tail light.
No white license plate light but I haven't been hassled about that. There's decent light on the tag, just red.

[RAFster122s]

Stuff in most auto parts stores I have seen are junk...
the incadescent bulb makes charge a lot for a pair of bulbs, they don't want to give you a superior LED as you would not be buying their bulbs.  Went into one parts place and they did not even carry a big name lighting maker but some no name I never heard of, bulbs needed so I bought some.  They didn't last.  I think I could have bought them at a dollar store and gotten better bulbs.  Live and learn.  Stick with GE or Sylvania on most auto bulbs if buying incadescent bulbs.