Motorcycle Rear Sprocket 48T 51T G 450 X Street Legal Fit For BMW G450 X 2008-2011 G450X Street Legal 2009 520 48T 51T rear sprocket direct bolt on mounting , aligns with hub , no extra or needed stable power transmission , reduces chain vibration , delivers smooth acceleration during offroad riding solid blank , tooth , polished tooth surface to lower chain friction loss OEM matched tooth count outer diameter , uniform tooth thickness for long term steady fit