Tire Size Speed Calculator

Speed Calculation Formula:

\[ Speed = \frac{RPM \times Tire Diameter}{336 \times Gear Ratio} \]

Speed (mph):

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1. What is the Tire Size Speed Calculation?

The Tire Size Speed calculation estimates vehicle speed based on engine RPM, tire diameter, and gear ratio. This formula is essential for automotive enthusiasts, mechanics, and engineers to understand vehicle performance characteristics.

2. How Does the Calculator Work?

The calculator uses the speed calculation formula:

\[ Speed = \frac{RPM \times Tire Diameter}{336 \times Gear Ratio} \]

Where:

\( RPM \) — Engine revolutions per minute
\( Tire Diameter \) — Tire diameter in inches
\( Gear Ratio \) — Final drive gear ratio (unitless)
\( 336 \) — Constant conversion factor

Explanation: The formula calculates vehicle speed in miles per hour by considering the relationship between engine rotation, tire size, and gear reduction.

3. Importance of Speed Calculation

Details: Accurate speed calculation is crucial for vehicle tuning, gear ratio selection, performance optimization, and understanding the relationship between engine RPM and actual road speed.

4. Using the Calculator

Tips: Enter RPM as revolutions per minute, tire diameter in inches, and gear ratio as a unitless value. All values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is the constant 336 used in the formula?
A: The constant 336 is derived from unit conversions that transform inches and revolutions per minute into miles per hour.

Q2: How do I measure tire diameter accurately?
A: Measure from the ground to the top of the tire while properly inflated and under load, or use manufacturer specifications for the exact tire size.

Q3: What affects the accuracy of this calculation?
A: Tire wear, inflation pressure, transmission slip, and actual rolling radius under load can affect the accuracy of the calculation.

Q4: Can this formula be used for different speed units?
A: The formula specifically calculates mph. For km/h, a different conversion factor would be needed.

Q5: Does this account for transmission gear ratios?
A: This formula uses the final drive ratio. For specific gear calculations, you would need to multiply by the individual transmission gear ratio.