I am thinking about installing crash bars (engine guards) on a 06 street bob. Dothey really help in a crash or are they just for looks?
Sssshhhhhh! Don't call them Crash Bars !! You'll get told off.
We call them Crash Bars in UK but most of the good folks on this site prefer to call them Engine Bars or Highway Bars. As Glider says it's probably a misnomer as they won't save a whole lot in a crash but they can protect important bits (including legs) in a low speed fall or ground-kiss.