Understanding Tire Markings
Laws require tire manufacturers to place standardized information on the sidewall of all tires.
This information identifies and describes the fundamental characteristics of the tire. It also
provides the tire identification number (TIN) for certification of safety standards, and in case of
a recall.
1
Tire category. P indicates that the tire is for passenger vehicles.
2
Tire width. This 3-digit number is the width (in millimeters) of the tire from sidewall edge
to sidewall edge.
3
Aspect ratio. This 2-digit number is the sidewall height as a percentage of the tread
width. So, if the tread width is 205 mm, and the aspect ratio is 50, the sidewall height is
102 mm.
4
Tire construction. R indicates that the tire is of Radial ply construction.
5
Wheel diameter. This 2-digit number is the diameter of the wheel rim in inches.
6
Load index. This 2 or 3-digit number is the weight each tire can support. This number is
not always shown.
Wheels and Tires
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MODEL X Owner's Manual
