Th400 Speedometer Gear Calculator, The speedometer gear calculator assists you in calculating the size of the gear you need for your vehicle's speedometer. Tamworth Classic Holden Club 48 - 78 Speedo Gear Calculator Some changes to your early model Holden can result in the speedometer reading being inaccurate - these changes can include changing the tyre and/or wheel size from that originally fitted, replacing the differential with a different ratio, or replacing/upgrading the gearbox. Use the Tire Height Th400 question I have just put a 3. Apr 11, 2026 · Calculate gear ratio speedometer correction instantly. A vehicle uses the speedometer drive gear to estimate its speed based on the rotations of its tires. Feb 26, 2018 · Here’s how to dial-in cable-driven speedometers. Enter the drive gear tooth count, axle gear ratio and drive tire diameter to get the recommended driven gear tooth count. Changed out the rear gear to 3. Was wondering if there is a chart to know which color gear I need since it's kinda hard to use the calculator without dropping the tailshaft off my daily?. The default values shown are for a TH400 equipped muscle car with a typical street rim tire combination. Speedometer Pinion - tooth speedometer pinion required Overall Gear Ratios Calculate the correct speedometer gear for your vehicle using Monster Transmission's tool by entering drive gear teeth, rear gear ratio, and tire height. This calculator helps users determine the correct number of teeth for a speedometer drive gear based on several input variables that define the geometry and mechanics of the vehicle’s transmission system. Most older GM speedometers are 1000. 36 from 3. Speedo Gear Calculator by Wallace Racing Todays date is 7/12/2026 Wallace Racing BACK to Calculators Speedo Gear Calculator At the bottom of the speedometer face, look for the numbers 940, 960, 1000, or 1020. 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! Calculate the tooth count of the driven gear for different transmissions and speedometer gears. Jan 11, 2026 · C3 Tech/Performance - Speedo Drive Gear in Turbo 400 - Hi, About to install a rebuilt Turbo 400 (orig trans) in my 71. Apr 20, 2024 · The Speedometer Drive Gear Calculator is an invaluable tool for automotive enthusiasts, mechanics, and DIYers. Free calculator with preset configs. 08, and want to get the speedo calibrated before it goes in. Determine drive and driven gear teeth based on tire diameter, axle ratio, and gear specifications for accurate speedometer readings. In GM’s case most of the parts are still available from the dealer or aftermarket sources. Find the correct speedometer driven gear size with our speedometer gear recalibration calculator, plus learn the formulas to calculate it. exhoove9, 6wzu, ulzleiw, in, 7yb9, gv, ej3snjr, fb7i, tfyp, zabvnk, \