Speedometer drive gear pinion 13t. (MZA) - Simson S70, S83, SR50, SR80 Note: Speedometer drive gear pinion 13 teeth. / Designed for 16 teeth sprocket. Can be used for: Simson S70, S83, SR50, SR80 The product of the MZA, which is the exclusive holder of the SIMSON brand. GPSR Contact: MZA Meyer–Zweiradtechnik GmbH, Baunsbergstr. 60-62, 34131, Kassel, Germany, gpsr@mza.de