1. What is a Tire Size Calculator?

Definition: This calculator estimates vehicle speed based on tire diameter and engine RPM.

Purpose: It helps automotive professionals and enthusiasts understand the relationship between tire size, RPM, and vehicle speed.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( S \) — Speed (miles per hour)
• \( RPM \) — Engine revolutions per minute
• \( TD \) — Tire diameter (inches)
• \( \pi \) — Pi (approximately 3.1416)
• 1056 — Conversion factor (combines unit conversions)

Explanation: The formula calculates how far the vehicle travels per minute based on tire circumference and RPM, then converts to miles per hour.

3. Importance of Tire Size Calculations

Details: Proper tire size calculations are crucial for speedometer accuracy, gear ratio selection, and overall vehicle performance.

4. Using the Calculator

Tips: Enter the engine RPM and tire diameter in inches. Both values must be > 0 for calculation.

5. Frequently Asked Questions (FAQ)

Q1: Where does the 1056 conversion factor come from?
A: It combines conversions from inches to miles (63360) and minutes to hours (60): 63360/60 = 1056.

Q2: How do I measure tire diameter?
A: Measure from the ground to the top of the tire, or calculate using: (wheel diameter) + 2*(sidewall height).

Q3: Does this account for tire slippage or deformation?
A: No, this is theoretical speed. Actual speed may vary due to tire flex, slippage, or load.

Q4: Can I use this for different speed units?
A: The result is in mph. For km/h, multiply the result by 1.60934.

Q5: Why is tire size important for speed calculation?
A: Larger tires cover more distance per revolution, increasing speed at the same RPM compared to smaller tires.