i have the stock windscreen but the helmet just has a non aero dynamic shape and the wind catches it mad easy...i can be completely under the windscreen and on a windy night it will get me...and it is not my riding possition as i have tried many...the cheap ass vega helmet i had before this was even worse...the shoie i had before that was perfect but it is also bout 700 bux so you get what you pay for...this is a nice hemet but it is not perfect thats all im saying...