How many tire sizes are there

The speed index rating is also a relevant factor when choosing a tire. Make your tire size selection in strict accordance with vehicle documents and tire manufacturer recommendations. For example, fitting inch-diameter wheels to a car that is designed to have inch-diameter wheels will change the ride height.

That means the car body will be higher off the ground. There will also be a slight increase in top speed, and the speedometer will no longer be accurate. Last but not least, the car will accelerate slower. Switching to different tire sizes can only be done in compliance with all legal requirements and regulations — plus the recommendations of the vehicle, wheel, and tire manufacturers.

The internal construction of tires fitted on any vehicle must either be radial or bias-ply. Fitting mixed tire constructions bias-ply and radial together for cars, caravans, and other light trucks is unsafe and illegal. The only permissible exception is the use of a spare tire for an emergency. Concerning the choice of wheels or rims, the same guidelines apply. Motorists must use the standard wheels or rims approved by the vehicle manufacturer as recommended.

For optimal safety and performance, replace all four tires at the same time. While it is possible to switch out less than four tires at the same time, you should follow a couple of guidelines regarding tire size. If only replacing one or two tires, for example, ensure that each one is the same size and has the same load index and speed rating as specified by the car manufacturer.

Choose the tire size for comparison with your stock tire size and click on 'Compare Selected Sizes' for immediate results. None of the three numbers mean anything without the other two. The tire size comparison calculator on tiresize.

All you need to do is enter two metric or standard tire sizes and click on the 'Compare' button. If you're looking for tires different to stock size, the calculator includes an additional useful tool. It displays examples of speedometer readings using the first tire, and the real speed you'd be going if you fitted the second tire.

Tire technology is always evolving, but your tires will always be among the most important components on your car.

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By Vehicle. Buying Experience. Auto Services. About Us. Sign In My Account. Let us help you read your tire size to find the right tire for your vehicle. High Flotation Tires. Passenger Car Tires. Expandable Link 14 Inch Tires. Expandable Link 15 Inch Tires. Expandable Link 16 Inch Tires. Expandable Link 17 Inch Tires. Expandable Link 18 Inch Tires. Expandable Link 19 Inch Tires. Expandable Link 20 Inch Tires. Expandable Link 21 Inch Tires.

Expandable Link 22 Inch Tires. Standard Passenger Tires Most tires will indicate the size on the sidewall in the following order: Tire Width in this example Aspect Ratio 60 in this example Rim Diameter 16 in this example. High-Flotation Tires High-flotation tires will indicate the size on the sidewall in the following order: Overall Diameter 35 in this example Section Width How to Buy Tires Online.

Buy the right tire in a few simple steps. Learn more about how it works. How to Compare Tires. Tire Size Calculator. Use the Goodyear Tire Finder, our tire size calculator, to help you find the right tire. Signup form component footer title. Email Address. If the tire size begins with a T, it means that the tire is a temporary spare.

Also known as mini spares or space savers, temporary spares are designed for short-term use until the regular tire is repaired or replaced. Tires beginning with ST are special trailer tires and should only be used on car, boat, or utility trailers.

Euro-Metric tire sizes ending with a C are commercial tires, for use on delivery trucks and vans capable of carrying heavy loads. In addition to the C designation, these sizes are also branded with a load range and service description rating load range B, C, or D. The three digits following the service type prefix if present tell us the cross-sectional width of the tire in millimeters. In the example above, the tires width, measured from the widest point of the inner sidewall to the widest point of the outer sidewall when properly mounted, is millimeters.

The section width can be converted to inches by dividing the width in millimeters by The two-digit number that usually follows the tire's section width tells us the aspect ratio, or tire profile measurement.

A lower aspect ratio means a lower-profile tire with a shorter sidewall, while a tire with a higher aspect ratio will have a taller sidewall and look more like a donut. Because we know that the tire size shown in this example has a section width of 8. Again using our example tire size from above, the 17 means that the tire should be matched to a inch diameter wheel.

Tires usually come in the following widths in inches : 8, 10, 12, 13, 14, 15, 17, 18, 19, 20, 22, 23, 24, 26, and Tires in these sizes are typically found on most passenger cars, light-duty light trucks, SUVs, minivans, and vans. Tires with a rim diameter measured in inches are called "inch rim" sizes. In addition to the inch rim sizes, there are also some unique tire sizes out there. Although not as common, tires are made in half-inch diameters for some heavy-duty light trucks, box vans, and heavy-duty trailers.

These sizes are usually Tires and wheels with unique rim diameters should never be combined with traditional inch rim tires and wheels.