What Do Tire Size Numbers P205 55R16 Mean?

by Philip McIntosh

Automobile tires are marked with a series of letters and numbers that provide information about tire structure and dimensions. Understanding this code is important when selecting tires for a particular vehicle or application.


The P indicates the tire is for use on a passenger car.


This number indicates the section width--the maximum width in millimeters from the outer sidewall to the inner sidewall; in this case 205 millimeters.


This is the sidewall height-to-width aspect ratio given as a percent. The 55 means that the sidewall height is 55 percent of the tire width.


The letter after the aspect ratio indicates the style of construction. R means it is a radial tire.


The number following the construction code is the wheel size in inches. This tire is designed to fit a 16-inch diameter wheel.


About the Author

Philip McIntosh has more than 30 years of experience as an equipment engineer, scientific investigator and educator. He has been writing for 16 years, and his work has appeared in scientific journals, popular science magazines, trade journals and on science and technology websites. McIntosh holds a B.S. in botany and chemistry, and an M.A. in biological science.

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