Abstract: There is disclosed an adjustable single-sprocket system including a sprocket having an opening for an axle, the sprocket having teeth about a perimeter of the sprocket, wherein the teeth of the sprocket are for engaging a bicycle chain, an adjustment dial, having an opening for the axle, the adjustment dial incorporating at least two adjustment ramps along a dial side closest to the sprocket, and a camming spacer, having an opening for the axle and including at least two camming ramps to engage with the at least two adjustment ramps to increase or decrease distance of the sprocket from the adjustment dial along a rotation axis about the sprocket as the adjustment dial is rotated about the rotation axis in a first direction or a second direction.