I have had 3 major motorcycle wrecks. Two head ons... And here is my take on helmets.
This is from the big California 10 year motorcycle crash statistics data dump.
Quote:Helmets reduce closed head injury in direct proportion to increased spinal trauma. (Save your head and break your neck)
Over 60% of head impacts are to the face and chin.
I do not always use a helmet, but when I do, it is full face with a solid chin guard. The reason is that at slow speeds in Houston summers the heat can be more of an accident risk... On the highway, or in winter, I use the full face. I have a gouge in a full face, and a scar on my chin from a 3/4 to tell me why.
Also, if you use a 3/4 or shorty, you get less than half the protection and all the spinal trauma risk.