PORSCHE SPECIFIC GEAR CALCULATOR Need custom ratios? Try our universal gear calculator Questions? Read our User & Collaboration Guide, call us at 510-907-9700 or email us. Ready to buy gears? Shop Now Use this form to email a customized PDF gear chart to yourself, your team, or to us at sales@retro-sport.com * Send to email: * Name: * Year / model: Phone: Bottom: Peak Torque Line RPM Mid: Shift Point Line RPM Top: Red Line Max RPM Tire Diameter (in) Calculated tire circumference from diameter (in inches) Select trans type > 356 901 & 904 915 924-G31 924-016 930 935 962 950 / G50 950 / G50 52 950 / G50 C4 951 968 993 996 GT2/3 996 / 986 987 ALL Shift Point MPH RedLine Shift MPH Shift Point RPM Drop Red Line Shift RPM Drop [Dynamic Dropdown] [Dynamic Dropdown] [Dynamic Dropdown] [Dynamic Dropdown] [Dynamic Dropdown] [Dynamic Dropdown] [Dynamic Dropdown] Optional Tire Size Calculator Enter the width, aspect ratio, & rim diameter, then make sure to copy and paste the calculated diameter into the "Tire Diameter" field above. Width (mm) Aspect Ratio Rim Diameter (in) Diameter (in)