Math & Engineering
Tire Size Calculator
Calculate tire dimensions including width, aspect ratio, and overall diameter
Enter tire dimensions to see results
Related to Tire Size Calculator
The Tire Size Calculator uses standard tire measurement conventions to calculate various dimensions of a tire based on its size code. The calculator takes three primary inputs: section width (in millimeters), aspect ratio (as a percentage), and wheel diameter (in inches). Using these measurements, it performs several calculations to determine important tire dimensions.
Understanding Tire Size Codes
A tire size code like 205/55R16 breaks down into three parts: the section width (205mm), the aspect ratio (55%), and the wheel diameter (16 inches). The 'R' indicates radial construction, which is standard for modern tires.
The calculator performs the following calculations: 1. Section Height (Sidewall Height) = (Section Width × Aspect Ratio) ÷ 100 2. Overall Diameter = Wheel Diameter + (2 × Section Height in inches) 3. Circumference = π × Overall Diameter 4. Revolutions per Mile = 63,360 ÷ Circumference
The calculator provides several key measurements that are crucial for understanding tire dimensions and performance characteristics. Each measurement serves a specific purpose in tire fitment and vehicle performance calculations.
Key Measurements Explained
- Section Width: The tire's width from sidewall to sidewall in millimeters - Section Height: The height of the tire's sidewall - Overall Diameter: The total diameter of the mounted tire - Circumference: The distance around the tire's outer edge - Revolutions per Mile: How many times the tire rotates in one mile
These measurements are essential for: - Ensuring proper tire fitment on your vehicle - Calculating speedometer accuracy - Determining ground clearance - Comparing different tire sizes - Understanding how tire size affects vehicle performance
1. What does the aspect ratio of a tire mean?
The aspect ratio is the height of the tire's sidewall expressed as a percentage of the tire's width. For example, if a tire has an aspect ratio of 55, it means the sidewall height is 55% of the tire's width.
2. How does tire size affect vehicle performance?
Tire size affects various aspects of vehicle performance including handling, acceleration, braking, fuel efficiency, and speedometer accuracy. Larger tires generally provide better stability but may reduce acceleration, while smaller tires might improve fuel economy but decrease ground clearance.
3. Why are revolutions per mile important?
Revolutions per mile is crucial for calculating accurate vehicle speed and ensuring proper speedometer calibration. It also affects gear ratios and overall drivetrain performance. Different tire sizes will result in different revolutions per mile, which can impact your vehicle's actual speed versus what the speedometer shows.
4. Can I use this calculator for any type of tire?
This calculator works for any standard passenger car, light truck, or SUV tire that uses the standard P-metric or metric sizing system. It may not be suitable for specialty tires or non-standard sizing conventions used in some industrial or agricultural applications.
5. What is the scientific source for this calculator?
This calculator is based on standardized tire measurement principles established by the Tire and Rim Association (TRA) and the European Tyre and Rim Technical Organisation (ETRTO). The mathematical formulas used are derived from geometric principles and industry-standard calculations for tire dimensions. The conversion factors and measurement relationships are based on the international tire sizing system standardized by ISO 3877-1:1978 and updated specifications from the International Organization for Standardization (ISO).