How fast do you go with the windscreen up in the cab? I didn't notice anything in the manual about speed restrictions.

 

I used mine on the autobahn. Does that give you any hint?

 

Only as fast as your nerve and or traffic situational awareness will allow!!

 

Same here on the Autobahn been up to 158 MPH with the top down, 179 MPH with top up. I can say at those speeds they are not of much use and usually I just put the windows up and leave the screen off. Of course the weather here was nice in July but horrible in August so not much fun in the sun time.
Cheers

 

Mach 1!