JCB JS200 hub reduction gear JCB JS200 hub reduction gear (05/903821) The presented toothed ring is used in the upper row of satellites in JCB excavator reduction gears. It is used in models JS190, JS200, JS210, JS220, JS235, JS240, JS260, JZ235, JZ255. Its catalog number is 05/903821. The ring has a diameter of 230 mm, a height of 24 mm and 78 teeth. The JCB JS200 securing ring is made of a material whose key feature is resistance to premature damage.