Convert Tire Sizes

Tires play a crucial role in determining the overall performance, safety, and efficiency of any vehicle. Therefore, understanding tire sizing can be advantageous for motorists, whether for replacement purposes or when trying to alter the performance characteristics of a vehicle.

When it comes to tire sizes, there are two common types of measurement systems: metric and imperial. The metric system is more widely adopted worldwide, but the imperial system, measured in inches, is still used in some countries, notably the United States. So, if you are looking to convert metric tire size to inches, you have come to the right place. Our easy to use tire size conversion calculator will help you get the equivalent dimensions of any metric tire size in inches.

Enter tire size below to convert it to inches, or browse the tire size conversion chart.

Keep in mind that some tire specifications may vary slightly from the calculations. Specs are based on a properly inflated tire mounted on the measured rim size and not installed on the vehicle. Measuring tire specs under the weight of the vehicle will produce slightly different results due to the added load.

Tire Size Meaning

Tire size refers to the standardized measurements used to describe the dimensions of a tire. These measurements provide important information about the tire's width, aspect ratio, construction type, and rim diameter. Understanding tire size is essential for selecting the right tires for a vehicle or determining compatibility when replacing existing tires. Learn more about how to read tire size.

Tire Width

Tire width, also referred to as section width, is a measurement in millimeters of the distance from the widest point of a tire's outer sidewall to the widest point of its inner sidewall when mounted and measured on a specified width wheel. This measurement varies depending on the tire's design and purpose.

The tire width has a direct impact on the tire's contact patch, or the area of the tire that is in contact with the road. A wider tire typically has a larger contact patch, which can improve traction, but may also increase rolling resistance and reduce fuel economy. Always make sure that the tire width is suitable for the wheel width and vehicle for safe operation.

Tire Sidewall Height

Tire sidewall height, also known as aspect ratio or profile, is the vertical height of a tire from the edge of the rim to the tread. It is typically expressed as a percentage of the tire's width.

The tire's sidewall height can have a noticeable effect on the vehicle's handling characteristics. Tires with a lower aspect ratio (low-profile tires) have less sidewall flex and can provide sharper steering response and better high-speed stability. However, they might also deliver a harsher ride and be more vulnerable to damage from road imperfections or potholes. Conversely, tires with a higher aspect ratio will have more sidewall flex, which can provide a smoother ride but might also result in less precise handling.

Tire Diameter

Tire diameter is the distance measured across the tire, when it's fully inflated and not under load. It's also called the overall diameter, and includes the tread, or rubber part of the tire, and the metal rim to which it's attached, from one edge to another, passing through the center.

For the actual tire diameter, you would need to add the height of two sidewalls to the diameter of the wheel. You can calculate the height of the sidewall by multiplying the tire width by the aspect ratio, then multiplying that by 2 and converting from millimeters to inches (since wheel diameter is usually measured in inches), then adding the wheel diameter.

Rim Diameter

The rim diameter is the diameter of the wheel on which a tire is mounted. It represents the inside diameter of the tire that fits onto the wheel, and corresponds to the distance from one edge of the rim to the opposite edge, passing through the center of the wheel.

It's important to note that this measurement doesn't include the tire itself. It is just the diameter of the rim on which the tire sits.

Tire Circumference

Tire circumference refers to the distance around the outer edge of a tire. It is the measurement of the length of the tire's circumference when it is fully inflated and mounted on a rim.

Keep in mind that tire circumference can vary slightly based on factors such as tire wear, inflation pressure, and the specific design of the tire.

Tire Revolutions

Tire revolutions refer to the number of times a tire completes a full rotation or revolution while it covers the distance of a mile or a kilometer.

The number of tire revolutions can be used to measure the distance traveled by a vehicle or to calculate various vehicle parameters such as speed, odometer readings, and fuel efficiency.

Popular Tire Size Conversions

Check out the tire conversion chart for metric tire conversion to inches.

All listed guides, data and/or calculations are for informational purposes only. TireConverter.com does not warrant or make any representations regarding the accuracy of or the results of the use of this information.