Small diameter sprocket ring for low gear ratio on bicycle has inside diameter chosen to fit on pedal shaft and has four holes partially surrounded with reinforcing rings to accommodate fastening screws

摘要

The low gear ratio sprocket ring (3) may have 20 equispaced teeth (2) on its outside diameter. It has a circular central aperture to accommodate the pedal shaft. The sprocket ring has four holes (1), partially surrounded by thickened portions (4) to act as reinforcing rings, to accommodate fastening screws. Four thickened reinforcing regions (7) are formed on the other side of the thin ring (5) from the screw hole reinforcements.