Porsche 993 with G50/21 Transmission with RS 1st Gear RPM to MPH Graph Transmission Gear Ratios: 3.154, 2.150, 1.560, 1.242, 1.024, 0.820 Move mouse over the graph to see exact RPM / MPH. Porsche 993 with G50/21 (Euro) Transmission RPM to MPH Graph Transmission Gear Ratios: 3.818, 2.150, 1.560, 1.242, 1.024, 0.820 Move mouse over the graph to see exact RPM / MPH. Porsche 993 with G50/20 (US) Transmission RPM to MPH Graph Transmission Gear Ratios: 3.818, 2.048, 1.407, 1.118, 0.928, 0.775 Move mouse over the graph to see exact RPM / MPH. Rear Differential Gear Ratio: 3.444 Redline RPM: 6750 Rear Tire Size: 255/40/17