How Tire Sizing Works
Learn how metric and flotation tire sizes work, including width, aspect ratio, construction, and rim diameter.
A common metric tire size such as 225/50R17 describes section width, aspect ratio, construction, and rim diameter.
In 225/50R17, 225 is the nominal section width in millimeters, 50 is the aspect ratio, R indicates radial construction, and 17 is the rim diameter in inches.
Flotation sizes such as 31x10.50R15 use a different format, usually indicating approximate overall diameter, section width, construction, and rim diameter.
Important reference note
Treadsley tools are informational reference utilities only. They do not replace vehicle manufacturer guidance, tire manufacturer guidance, applicable legal requirements, or inspection by qualified tire and service professionals.