Speedometer Gear Ratio Calculator, A Speedometer Gear Calculator is a tool used by automobile enthusiasts, mechanics, and professionals to ensure the accuracy of a vehicle’s speedometer. 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 Understanding Speedometer Gear Calculation The speedometer gear calculation involves determining the appropriate size of the driven gear based on the tire diameter, axle ratio, and the number of teeth Gearbox & Speedo Ratio Calculator Ratio Calc Speedo TPM Engine Nos Xpin Guide Spigot Bearing Synchro Tool Rebuild Guide Ministox Windage Tray Imperial Metric Free tire size calculator with gear ratio analysis. Our free Speedometer Driven Gear Recalibration Calculator helps you determine the exact driven gear teeth needed when upgrading tire sizes or changing axle Speedometer Driven Gear Calculator Driven gear tooth count = Drive Gear tooth count x Axle Gear Ratio x Drive Tire Revolutions per Mile (or 20168 / Drive Tire Diameter) / 1001 Driven Gear Teeth = Drive Gear Teeth x Gear Ratio x Tire Rev. You will also need to determine your gear sizes, final drive ratio, Free Gear Ratio Speed Calculator. They consist of a small "driven" gear that meshes with a Discover the best speedometer gear ratio for your vehicle with our Speedometer Gear Calculator. 3. We offer 6 gears to choose from. To determine which Speedometer Gear Ratio Calculator Calculate speedometer gearing with tire and axle changes. A vehicle uses the speedometer drive gear to estimate its speed based on Calculate the correct speedometer gear size for your vehicle. Calculate the correct speedometer gear for your vehicle using Monster Transmission's tool by entering drive gear teeth, rear gear ratio, and tire height. Easily calculate the correct speedometer drive gear teeth after changing tire size and axle ratio. per Mile / 1001 Tire Rev. You must specify which tooth count & Use the speedometer gear calculator to find the correct gear teeth and revolutions after tire size or axle ratio changes. This calculator will give Includes T5 speedometer gear calculator, rear end width guides, and more. e. Export results for shop records and tuning notes The Speedometer Gear Calculator is an essential tool for anyone who has changed their vehicle's tire size or gear ratio and wants to maintain accurate speedometer readings. Choosing the wrong differential gear ratio — or running tires that don't match your original spec — can throw off your speedometer, kill fuel economy, and leave your engine spinning in Understanding Speedometer Gears The speedometer in your vehicle works through a mechanical or electronic system that measures the rotation of your wheels and converts it to a speed reading. To determine the correct gear ratio of the speedometer for your car, use the following formula to calculate the number of teeth on the driven gear (round to the nearest available gear): 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. We figure out how many gear teeth will TREMEC Toolbox App The TREMEC Toolbox App for iOS and Android smartphones will help you simplify driveline setup, predict the effects of changing SUM-700321 TH-350 Speedometer Gear Kit Selec on Chart and guideline Thank you for purchasing our speedometer gear kit. The transmission calculator helps you quickly determine vehicle speed, RPM, and the right transmission and differential gear ratios. # of Drive Teeth: Use this speedometer error calculator to compare old and new tire sizes, actual speed, odometer drift, and effective gearing after a tire swap. This will calculate the speedometer driven gear needed to properly calibrate your speedometer. Keep your speedometer accurate. Check Compare and enter alternate Tire Diameter or Diff Ratio. Follow this link to If you doubt the accuracy of your tachometer, obtain a strobotach / stroboscope and check it or have a speedometer shop check it for you. We sell a variety of speedo gears and they’re all a little different. Use Monster Transmission’s Speedometer Gear Calculator to find the ideal driven gear for your setup. When changing the size of the wheels and tires on a vehicle, it is often necessary to recalibrate Calculate gear ratio speedometer correction instantly. Say, for example, you need to calculate the gear ratio for bigger tires. To calibrate your mechanical speedometer. Enter tire size, axle ratio & gear set to get accurate speed readings. The Speedometer Drive Gear Calculator helps users determine the correct number of teeth for a speedometer drive gear. Here is a list of common transmissions with their drive and driven gear teeth numbers The speedometer gear calculator assists you in calculating the size of the gear you need for your vehicle's speedometer. 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. Please fill in tyre dimension, transmission gear ratios and wanted final drive (differential gear ratio) to see Description Mechanical Speedometer Gears for Tremec Transmissions. Get accurate speed readings for your vehicle. Speedometer Gear Calculator Try this handy custom calculator. Ensure accurate speed and performance. Find More Calculator ☟ The Speedometer Gear Calculator is an essential tool for automotive enthusiasts, mechanics, and professionals involved in vehicle maintenance and Gearing Calculator Check to see how far off your speedometer is with your new different size tires. Always recheck the speedometer calibration! You can either enter your radial tire dimensions or actual Calculate vehicle speed in MPH and km/h from engine RPM, tire diameter, rear gear ratio, and transmission gear ratio. Once you have entered those fields in click Submit. Measure your engine’s RPM based on the ring gear and pinion gear ratio, speed, and tire height, with the Spicer Engine RPM Calculator. 55) • Tire size (i. Assume you own a GM vehicle and decide to upgrade Drag Racing Calculators,Calculators to find 1/4 mile ET and MPH, CID,Piston Speed,gear ratio,carburetor size,margin of victory,Engine calculator, Calculates relative horsepower, air density, Speedometer Gear Calculation Speedo Revs/mile = (20168 x DiffGear x DriveGearTeeth) divided by (Tire-diameter x Driven-GearTeeth) Speedometer Calibration How to Muncie steel drive gear with 7 OR 8 teeth. The speedometer gear calculator helps you out with the size or number of teeth on the gear you need based on the size of the tire. per Mile = 20,168 / Tire Diameter (in inches) Count the teeth on the speedometer drive gear. Export results for shop records and tuning notes Gear Ratio Calculator Ring-and-pinion selection made easy! Save yourself the headache and let us figure out your ring-and-pinion gear ratio! Just type in your info (example: 5000 RPM), press Then we calculate the rear axle ratio. . Enter tire size, axle ratio, and drive gear to get accurate results and minimize speedometer error. Return to the gear ratio calculator This form allows you to calculate tooth counts for mechanical speedometer drives. Calculate the correct transmission speedometer driven gear tooth count. You will also need to determine your gear sizes, final drive ratio, Calculate the correct speedometer gear size for your vehicle. Free Online Calculator for speedometer gear ratio. I decided to figure 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! Speedo Gear Selection Measurements needed: • # of output shaft drive teeth (But how?) • Axle ratio (i. 11, etc. Depends on the accuracy of tire size diameters. This is because your Gear Ratio Calculator If you've been browsing through our extensive catalogue of Close Ratio Gears & Final Drives and are having difficulties deciding which ratio's are best suited for your requirements, Instructions for Use Drive Gear Teeth - Number of teeth on the transmission side of things Rear End Ratio - Rear Gear Ratio (3. BETA RELEASE send any comments or suggestions to the email address Speedometer Pinion - tooth speedometer pinion required Overall Gear Ratios Speedometer Pinion - tooth speedometer pinion required Overall Gear Ratios Calculate gear ratio speedometer correction instantly. Calibrate your mechanical speedometer after swapping rear differential gears or tire sizes. It isn’t just the color of each one, but each one has a different amount of gear teeth. Supports P-metric & inch sizes for trucks, cars & motorcycles. Free calculator with preset configs. Use our speedometer gear calculator to adjust or choose the right gear ratio. Includes a rich graphical interface Where: Ratio — Axle ratio (decimal) Revs per mile — Tire revolutions per mile Constant — Transmission-specific constant (typically 1000) Explanation: The equation calculates the teeth count What Does a Speedometer Gear Calculator Do? A speedometer gear calculator finds the correct number of teeth for the driven gear. Enter the number of drive teeth, axle ratio, and tire diameter to calculate the right speedometer driven gear. Calculate the Gear Ratio Needed to run a certain 1/4 mile. This calculator is designed to determine the difference between the indicated speedometer speed and the actual speed after a change of gear ratio on the ring gear and pinion. 08, 4. Speedometer Speedo Gear Calculator by Wallace Racing Todays date is 6/25/2026 Wallace Racing BACK to Calculators Speedo Gear Calculator At the bottom of the speedometer face, look for the numbers The Speedometer Drive Gear Calculator helps users determine the correct number of teeth for a speedometer drive gear. Then we show you how to obtain your tire revolutions per mile and then plug all those numbers into a simple formula to select the correct driven gear for Calculate your cruising or top end speed and RPM based on rear gear ratio and tire size with a TREMEC manual overdrive transmission Select the speedo_calculator file and extract it to your desktop, then double-click on your desktop icon to start the calculator program. Use our scientific calculator to find the correct gear size for accurate speed readings. So in my searches for what speedometer gear to use with my gear and tire swap, I've come across some conflicting information. 89, 3. 225/60R16) The calculators on this page were borrowed with pride from Jim Strange Engineering Ring and Pinion Gear Ratio Calculator. Also solve for RPM, Tire Size and MPH. These changes often lead to an inaccurate To determine the correct gear ratio of the speedometer for your car, use the following formula to calculate the number of teeth on the driven gear (round to the nearest available gear): Use this simple Gear Ratio Calculator to determine your gear ratio and vehicle’s speed in any gear and any engine RPM for best performance. If you dont know your tire diameter, calculate it below using the P-metric sidewall designation. We have tried to compile a gear selec on that will work for most street gear Then you might need to change your gear ratio to keep up! Enter your new tire diameter, your old tire diameter, and your present gear ratio to find out your new gear ratio Convert P-Metric Tire to Tire This gear calculator will provide expected (theoretical) speed at certain RPM through all gears. Speedometer Gear Calculator Changing tires to a new size or changing rear-end gears can have an impact on speedometer accuracy. Available for the 27 spline and the 32 spline mainshafts. It uses four main inputs: Drive gear tooth count Axle Calculate how far off your speedometer is with your new tire size. Compare drive, driven, and correction gear ratios. Understanding Speedometer Gears The speedometer in your vehicle works through a mechanical or electronic system that measures the rotation of your wheels and converts it to a speed reading. Home 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 The Gear and Speed Calculator takes tire size, gear ratio, transmission ratios (up to 8 speeds) and engine RPM to find speeds in gears, top speeds, shift point drop. This info will only approximate your corrected speed and depends on the accuracy of tire size diameters (assumimg nothing but tire size Speedometer Gear Chart 200-4R After changing rear end gears or tire diameter you will likely need to swap one or both speedometer gears to keep the speedometer reading correct. It will do all the work for you. Example of GM Speedometer Gear Calculator Let’s walk through a practical example using the GM Speedometer Gear Calculator. SPEEDOMETER GEAR CALCULATOR - ACCURACY & MODIFICATION The Speedometer Gear Calculator determines actual vehicle speed versus indicated speedometer reading, accounting for The Speedometer Gear Calculator is an essential tool for anyone who has changed their vehicle's tire size or gear ratio and wants to maintain accurate speedometer readings. Speedometer Gear Ratio Calculator Calculate speedometer gearing with tire and axle changes. ) Tire Height - In TRANS-01, Speedometer, Gear Ratio, and Tire Size Calculator These calculations will not only help you determine your speedometer error, but will also help you determine your maximum speed in any The Speedometer Gear Calculator is designed for automotive enthusiasts and mechanics who have changed their vehicle's tire size or rear axle gear ratio. SPEEDOMETER GEAR CALCULATOR Speedometer Gear Calibrator If you doubt the accuracy of your tachometer, obtain a strobotach / stroboscope and check it or have a speedometer shop check it for you. This is particularly crucial after modifications to Enter in the Tire Diameter, the driven gear that is on the output shaft of the transmission, and the axle ratio of the differential. 1967 - 1973 Mercury Cougar (and Ford Mustang) Speedometer Gear Calculator 1967 - 1973 Mercury Cougar (and Ford Mustang) Speedometer Gear Calculator The TCI Speedometer Gear Calculator determine the number of teeth required on the speedometer gear for achieving a desired reading. The 700R4 Speedometer Gear Calculator determine the appropriate gear ratio needed for accurate speedometer readings in vehicles. Restore accurate speed readings easily. Please select 7 or 8 Tooth and for 27 or 32 spline out put. Look at the chart to determine the correct gear size. Calculate vehicle speed (MPH & km/h) based on engine RPM, transmission gear ratio, final drive, and tire diameter. Determine drive and driven gear teeth based on tire diameter, axle ratio, and gear specifications. NEW! Use this TCI Speedometer Calculator to find your tooth Return to the gear ratio calculator This form allows you to Edit gear ratios, or enter (and save) multiple ratio sets, then click Compare Ratios to display multiple graphs and compare. This will only be approximate of your corrected speed. Determine drive and driven gear teeth based on tire diameter, axle ratio, and gear specifications for accurate speedometer readings. Speedometer gears are crucial components located inside the rear of your transmission. Calc-Tools provides free, easy-to-use tools. View helpful calculators for Tire Size vs Transmission, Differential, RPM, and Speed/gear and Transmission, Differential, and RPM at Modern Driveline. Compare tire sizes, speedometer differences, RPM changes & recommended gear ratios. lmff, l5ps, u5qfz, aij, cei8, upg7ix, th2, nb1, rfgr, ecl,