1. What is the Rims & Tires Size Calculator?

The Rims & Tires Size Calculator helps determine the overall diameter of a tire based on rim size, tire width, and aspect ratio. This is essential for proper vehicle fitment and performance.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( Rim \) — Rim diameter in inches
• \( Width \) — Tire width in millimeters
• \( Ratio \) — Aspect ratio (sidewall height as percentage of width)
• 25.4 — Conversion factor from mm to inches

Explanation: The equation calculates the total diameter by adding the rim diameter to twice the sidewall height (converted from mm to inches).

3. Importance of Tire Size Calculation

Details: Proper tire sizing is crucial for vehicle safety, speedometer accuracy, clearance issues, and maintaining proper gearing. Incorrect sizes can affect handling, braking, and fuel efficiency.

4. Using the Calculator

Tips: Enter rim size in inches, tire width in millimeters, and aspect ratio as a percentage. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why is tire diameter important?
A: Tire diameter affects speedometer readings, gear ratios, clearance, and overall vehicle dynamics.

Q2: What's a typical aspect ratio?
A: Common ratios range from 30-75%, with lower numbers indicating lower profile tires.

Q3: How much can I change my tire size?
A: Generally, staying within 3% of original diameter is recommended, but check your vehicle's specifications.

Q4: Does this calculator account for wheel width?
A: No, this calculates theoretical diameter only. Actual mounted dimensions may vary based on wheel width.

Q5: What about plus-sizing wheels?
A: When increasing rim diameter, you typically decrease aspect ratio to maintain similar overall diameter.