1. What is the Car Speed Formula?

The car speed formula calculates vehicle speed based on engine RPM, tire circumference, and gear ratio. It provides an accurate estimation of how fast a vehicle is moving under specific mechanical conditions.

2. How Does the Calculator Work?

The calculator uses the speed formula:

Where:

• \( RPM \) — Engine revolutions per minute
• \( C \) — Tire circumference in inches
• \( GR \) — Gear ratio
• \( 336 \) — Constant conversion factor

Explanation: The formula accounts for the relationship between engine rotation, tire size, and gear reduction to determine vehicle speed in miles per hour.

3. Importance of Speed Calculation

Details: Accurate speed calculation is crucial for vehicle performance tuning, gear ratio selection, and understanding how mechanical changes affect vehicle speed and performance.

4. Using the Calculator

Tips: Enter engine RPM, tire circumference in inches, and gear ratio. All values must be valid positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: How do I measure tire circumference?
A: Measure the distance around the outside of the tire, or calculate using tire diameter (Circumference = π × Diameter).

Q2: What is a typical gear ratio range?
A: Gear ratios typically range from 2.5:1 to 4.5:1 for most vehicles, with lower ratios providing better acceleration and higher ratios better top speed.

Q3: Why is 336 used in the formula?
A: The constant 336 converts inches per minute to miles per hour (12 inches/foot × 5280 feet/mile ÷ 60 minutes/hour = 1056, then adjusted for gear ratio calculations).

Q4: Does this work for all vehicle types?
A: The formula works for most wheeled vehicles but may need adjustment for vehicles with different drive systems or significant tire slip.

Q5: How accurate is this calculation?
A: The calculation provides theoretical speed. Actual speed may vary due to factors like tire wear, transmission efficiency, and road conditions.