A torsionally compliant sprocket system includes a first sprocket (250); a second sprocket (230) mounted in side-by-side relation to the first sprocket (250); a resilient member (270) that resiliently couples the second sprocket (230) to the first sprocket (250) to allow limited angular rotation of the second sprocket (230) with respect to the first sprocket (250); and a locking structure (300, 600, 700) that is biased toward an engaged position in which angular motion of the second sprocket (230) with respect to the first sprocket (250) is restrained and moves in response to rotation of the first sprocket (250) to a disengaged position in which angular motion of the second sprocket (230) with respect to the first sprocket (250) is permitted.