Quote: I was about to buy these, but before i do i have a question that hopefully someone can answer. Since the lenses are colored, why do we want the same color of bulb? Wouldn't using a white LED under the green lens give even more brightness? or is there a reason to go with an LED color the same as the bike's lens'?
Welcome to Physics 101. White light is a mixture of all colours. Lenses work by removing the unwanted colours from white light. LED's (except for ultra cheap dim ones) don't put white light through a filter, they create only the desired colour. "White" LED's aren't really white, they're a very light blue, which means there's NO red or yellow coming from the "white" LED. If you put a blue LED (even a very pale one) behind a red lens you'll remove almost all the light because the LED's not putting out any red light. A blue LED will work slightly better behind a green filter as green is a mixture of blue and yellow but you're still better off using green LED's behind a green filter.
Basically if you want to get the greatest amount of the outputted light from a LED to make it through the filter you should use the coloured LED closest to the filter's colour.
