You should not have to change concaves on the 85's. It is the same design, only larger, then my Challenger 660, and we don't change concaves for corn and beans. Might have to put filler plate on outside of the first or second concave for small grain or add wires to first one. If it is a corn and soybean combine they remove some of the wires on the first two concaves so you get more of the grain out of the rotor quicker.