Three mph would be about tops. If the beans are under 13 moisture, the stalks are less than 2.5 foot tall and dead. If the beans are in 30" rows you might get a little more speed.
That's where it seemed confortable.Sometimes a shade over when in shorter beans.30in rows and 9-10 %.Plants were dry but a few soft stems mixed in.Got to watching and couldn't believe the number of seeds flowing off the front of cutter bar(all new sickleandguards)in center of auger.Seemed worse than toward outer ends but visabilaty out there wasn't as good either.Head shatter was plenty all across.Found more on groud in center but not convinced it came off shoe.
30 inch rows 60 bushels_A 3mph is pushing it from a sickle bar on an F3. Nothing I see over shoe. Put in the PVC pipe on cutter bar to trip beans over for better feeding...really made a difference, plus virtually eliminated rocks too. I run Trimpe bars...Seymour IN. Those shattering beans do not roll of head as badly with pipe.