I have ran the Loewen concave in my walker machines for about the past 8 years and they are absolutley excellent. I would never even think of buying an OEM deere for my machines. The bars are thicker, wires are larger diameter, harder material is used, they stay straight longer and the leading edge on the first four bars, which are the critical ones for feeding,, stay with a sharper edge atleast four times longer than OEM. Ive seen also that sunnybrooke who makes solid cylinders and boronized rasp bars makes a concave with replacable front bars for small crain concaves. Makes good sense to me seeing how the only reason Ive replaced concaves in the past was that they wouldnt feed right and the edges of the cross bars are wore rounded. Also check out there feeder chains,,,, AWESOME. Chrome pins only in my opinion. The last feeder house chain I bought of theirs had over 3000 hrs on it, wore out three sets of sprockets before I send the entire rig to Mexico. And it only needed adjustment Once a season. As for my 50 Walker I will be putting in my sunnybrooke cylinder but am undecided on changing the concave yet. Good luck buddy.