Check the shanks for looseness after running a few (20-40) acres. The tension is preset at the factory, but can change due to movement of the bracket on the bolts and can cause the shank to chatter when running. To check, put your foot on top of the point and push sideways, if the shank moves easily, the rear spring bracket requires adjustment. First check all rear bracket bolts for tightness; then loosen the two bolts that go thru the shank. Then adjust the set screw until the shank is snug when pushing sideways with your foot. Firmly tighten the rear bracket on the shank and tighten the set screw lock nut.