How to Read Your Tire Size

A common tire size looks like this: P205/55R16 91H

• P = Tire type
• 205 = Tire width
• 55 = Aspect ratio
• R = Construction type
• 16 = Rim diameter
• 91 = Load index
• H = Speed rating

What Each Part Means

Tire Type
The first letter shows the type of tire. In this example, P stands for passenger tire. You may also see LT for light truck or T for temporary spare.

Tire Width
The three-digit number shows the tire’s width in millimeters. In this example, 205 means the tire is 205 mm wide.

Aspect Ratio
The two-digit number after the slash shows the height of the tire’s sidewall as a percentage of its width. In this example, 55 means the sidewall height is 55% of the tire’s width.

Tire Construction
The next letter shows how the tire is built. In this example, R stands for radial construction, which is the most common type for passenger vehicles.

Rim Diameter
The next number shows the wheel size the tire fits, measured in inches. In this example, 16 means the tire fits a 16-inch wheel.

Load Index
The next number shows how much weight the tire can safely carry. In this example, the load index is 91.

Speed Rating
The last letter shows the tire’s speed rating. In this example, H means the tire is rated for speeds up to 130 mph.