Actually, it's scientifically proven that yellow is much more slippery, generating less air friction and so allowing the bike to go faster...
Sorry, but no. He's why...
Microwaves don't like silver things, as they bounce off them. Hence, silver is slowest
In the visible spectrum, red is the slowest. Red has the least energy coming off the light waves
Yellow bikes follow red. Faster, true, but blue kicks its butt (as does Kawacrappy green).
Blue bikes are nearly faster, but purple bikes pin them to the wall.
And after purple, the light gets so energised and dark that all you're left with is black, as it heads towards Xray and Gamma ray speeds - the speed of light, and good at penetrating things (oo err!
)!!!