How to Use This Calculator
- Enter the Engine RPM (Revolutions Per Minute) of your vehicle. This is typically found in your vehicle's performance specifications or can be measured with a tachometer.
- Input the diameter of your vehicle's tires in inches or millimeters. This can usually be found in your vehicle's manual or by measuring the tire.
- Enter the gear ratio of your vehicle's final drive. This is the ratio between the driveshaft speed and the wheel speed, often found in your vehicle's performance specifications.
- Click the "Calculate" button. The calculator will then compute the vehicle's speed in miles per hour (MPH) based on the inputs.
- Use the "Reset" button to clear all inputs and start over if needed.
Working Principle
The calculator uses the following formula to determine vehicle speed:
Vehicle Speed (MPH) = (Engine RPM × Tire Diameter × π × Gear Ratio) ÷ 1056
This formula works by converting engine RPM to wheel rotations per minute, then to distance traveled per minute, and finally to miles per hour. The conversion factor of 1056 comes from the relationship between RPM, tire diameter, and distance traveled (60 minutes/hour × 1 mile/5280 feet × 12 inches/foot).
Applications
- Performance tuning: Determine the engine RPM at which your vehicle will reach a certain speed.
- Understanding vehicle dynamics: Analyze how changes in tire size or gear ratio affect vehicle speed.
- Drag racing: Calculate the necessary engine RPM to achieve optimal launch speeds.
- Off-road: Estimate speed capabilities for different terrains with varying tire sizes.