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RPM Calculator

Understanding RPM Calculation

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.

Formulas Used

Transmission Ratio:

$\text{Transmission Ratio} = \frac{\text{RPM} \times \text{Tire Diameter}}{336 \times \text{Vehicle Speed}}$

Wheel RPM:

$\text{Wheel RPM} = \frac{\text{Vehicle Speed} \times 336}{\text{Tire Diameter}}$

Calculation Example

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:

$\text{Transmission Ratio} = \frac{3500 \times 23}{336 \times 60} \approx 3.99$

Wheel RPM:

$\text{Wheel RPM} = \frac{60 \times 336}{23} \approx 877 \text{ RPM}$