The RPM (Revolutions Per Minute) calculation for a vehicle involves determining the rotational speed of the engine and the wheels based on the tire diameter, vehicle speed, and transmission ratio.
Transmission Ratio:
Transmission Ratio=RPM×Tire Diameter336×Vehicle Speed
Wheel RPM:
Wheel RPM=Vehicle Speed×336Tire Diameter
Suppose you are driving at 60 mph with a tire diameter of 23 inches and the engine RPM is 3500. Using the formulas:
Transmission Ratio:
Transmission Ratio=3500×23336×60≈3.99
Wheel RPM:
Wheel RPM=60×33623≈877 RPM