Tire Size Equivalent Calculator

Equivalent Diameter Formula:

\[ \text{Diameter} = \text{rim} + 2 \times \text{section\_height} \]

Equivalent Diameter (mm):

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1. What is a Tire Size Equivalent Calculator?

Definition: This calculator determines the overall diameter of a tire based on the rim diameter and sidewall height.

Purpose: It helps vehicle owners, mechanics, and tire professionals understand tire sizing and find equivalent sizes.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \text{Diameter} = \text{rim} + 2 \times \text{section\_height} \]

Where:

Diameter — Overall tire diameter (mm)
rim — Rim diameter (mm)
section_height — Sidewall height (mm)

Explanation: The total diameter is calculated by adding the rim diameter to twice the sidewall height (since there's sidewall on both sides of the rim).

3. Importance of Tire Size Calculation

Details: Proper tire sizing ensures correct speedometer readings, maintains vehicle handling characteristics, and prevents clearance issues.

4. Using the Calculator

Tips: Enter the rim diameter and section height in millimeters. Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Where can I find these measurements on my tire?
A: They're typically in the tire size code (e.g., 205/55R16 - where 16 is rim diameter in inches, 55 is aspect ratio).

Q2: How do I convert from inches to millimeters?
A: Multiply inches by 25.4 (1 inch = 25.4 mm). Our calculator works in mm for precision.

Q3: What's a typical section height?
A: This varies by tire type. Passenger tires often have section heights between 100-150mm.

Q4: Why is equivalent diameter important?
A: It affects speedometer accuracy, gearing, and ensures proper wheel well clearance.

Q5: Can I use this for plus-sizing calculations?
A: Yes, this helps maintain the same overall diameter when changing wheel sizes.