C4 Speedometer Gear Calculator, This method is purely calculations-based and you should always check your manufacturers specifications. The accompanying charts show what gears… 1967 - 1973 Mercury Cougar (and Ford Mustang) Speedometer Gear Calculator Apr 7, 2021 · My wifes 67 fastbacks speedo has always been off, I would say 10-12 miles per hour slow. Use the Spicer Transmission Ratio RPM Calculator to determine your engine’s RPM based on the transmission gear ratio, tire height, MPH, and ring and pinion gear ratio. It aids in accurately calculating the size or number of teeth needed on a speedometer's driven gear, based on the tire size and axle ratio of a vehicle. Jul 11, 2018 · How do I choose the correct speedometer gear. Any advice on how to choose correct gear? Thanks Calculator Instructions This calculator provides the necessary information needed in order to determine what transmission speedometer gear is needed in order to properly calibrate a speedometer. 1967 - 1973 Mercury Cougar (and Ford Mustang) Speedometer Gear Calculator Use this TCI Auto Speedometer Gear Calculator Formula for any GM, Ford or Chrysler vehicle. This is very useful when there is no established baseline from which to work from such as replacing a transmission in a vehicle that was purchased without a drive line! May 8, 2020 · Get the right speedometer gear for your 1979-98 Mustang based off of rear gear ratio & tire size! No guessing with this Mustang Speedometer Gear Calculator! Find the correct speedometer driven gear size with our speedometer gear recalibration calculator, plus learn the formulas to calculate it. Is there a way to determine the speedo drive gear without pulling the tailshaft housing? I really need to get my speedo showing the right speed. C4, so assuming 8 drive teeth, 2. somgt, inoo7, t8a, kk, 4og24fb, 0d, hch, 5df, tp, bbr,