1. What is a Tyre Diameter Calculator?

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

Purpose: It helps vehicle owners, mechanics, and tyre professionals ensure proper tyre fitment and maintain accurate speedometer readings.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Diameter \) — Total tyre diameter in millimeters
• \( Rim\ Diameter \) — Diameter of the wheel rim in millimeters
• \( Section\ Height \) — Height of the tyre sidewall in millimeters

Explanation: The total diameter is calculated by adding the rim diameter to twice the section height (since the tyre wraps around both sides of the rim).

3. Importance of Tyre Diameter Calculation

Details: Correct tyre diameter is crucial for maintaining proper vehicle clearance, accurate speedometer readings, and ensuring compliance with local regulations.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Where can I find rim diameter and section height?
A: These values are typically marked on the tyre sidewall (e.g., 205/55R16 where 16 is rim diameter in inches).

Q2: Why is tyre diameter important?
A: It affects speedometer accuracy, gear ratios, and vehicle clearance. Significant changes may require speedometer recalibration.

Q3: How does tyre diameter affect my vehicle?
A: Larger diameters may improve ground clearance but reduce acceleration. Smaller diameters may improve acceleration but reduce top speed.

Q4: Is this calculator specific to Australia?
A: While designed with Australian standards in mind, the calculation works universally. Always check local regulations.

Q5: Can I use inches instead of millimeters?
A: Convert inches to mm by multiplying by 25.4 before entering values, or use our Tyre Calculator Inches version.