Skip to main content eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJjb25zdW1lcktleSI6IjFlNzFkM2QwYmU4YzQ4YWJiOWU0OWMwYjhmOTcwYzFhIiwidXNlcklkIjoiY29uY2VudHJlayIsImlzc3VlZEF0IjoiMjAxNy0xMi0wN1QxNjozMjoyMy0wNTowMCIsInR0bCI6NjA0ODAwLCJ1c2VyIjoiY29uY2VudHJlayJ9.KEebqy9hklM0Nwam1ADwAXwwUSru0ivxmkkIrsxkINs
Share
Measure your engine’s RPM based on the ring gear and pinion gear ratio, speed, and tyre height.

In order to calculate the engine RPM based on ring gear and pinion gear ratio, speed and tire height, this calculator makes the following assumptions:

  1. You may not be sure of the type of transmission you are currently using. The results will then be:
    • Automatic transmission in Drive
    • Automatic transmission in Overdrive
    • 3-speed manual transmission in 3rd gear
    • 5-speed (or higher) manual transmission in the last gear
    • The ratios used for the transmissions are 0.70 for the automatic and 0.80 for the manual
  2. You know the ring gear and pinion gear ratio. See the Gear Ratio calculator in the Spicer Tool Kit to determine your ratio.
  3. You know the tire height in inches. See the Tire Height calculator in the Spicer Tool Kit to determine your tire height.
  4. The speed will be the vehicle speed, measured in miles per hour (MPH).