Gm Speedometer Gear Calculator, Use the Tire Height Calculate the right speedometer driven gear tooth count after changing tire size or axle ratio, and estimate speedometer error. If you didn't change speedometer gears, actual vehicle speed would 73. Calculate the right speedometer driven gear tooth count after changing tire size or axle ratio, and estimate speedometer error. Replacing a Speedometer gear, trying to figure out how many teeth you need for your new tire or rear axle ratio? This tool will help with the calculations. Free shipping to any USA address. 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. Aug 22, 2025 ยท A new 18 tooth speedometer gear for Aluminum Powerglide, Muncie and Saginaw 2-3-4 speed transmissions. This gear fits in steel bullet style speedo housings available separately. Speedometer Gears Formula for Calculating Speedometer Gears The following formula will work for any GM, Ford or Chrysler vehicle and 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. Whip out your calculator and follow along. vngy6e, np2, ay, 1skb, c6wqlb, pqkcj, xd4, ibsk, asfqh8, khe5,