With no windshield the wind wind hits you from the front. With only a windshield installed a lot of dust and chaff blows up and around from behind. Opening my vented windshield takes care of much of the dust from behind problem but if I close it I'd say you get more crud in the cab than going with no windshield. I have a rear window for winter use and fixed 1/4 doors that blocks anything from blowing in from behind.