Wind turbulance

[Aussie Steve]

You could be right ER. My helmet (RXT) has rear facing vents on top and a flaired ridge towards the lower back but it is a snug fit. I had the visor is down....didn't try it with it up maybe that would reduce the wind flow over the helmet. The wind seemed to be blasting then stopping in quick sucession...hard to explain but it caused my head to rapidly nod up and down to the extent I couldn't see my guages or the road clearly. I do know it wasn't the helmet moving on my head (too loose) Any Perth riders willing to go for a blast to get any idea's?