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.
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.
7 Speed rating. When stated, indicates the maximum speed (in mph) at which the tire can be used for extended
periods. Q=99 mph (160 km/h), R=106 mph (170 km/h), S=112 mph (180 km/h), T=118 mph (190 km/h),
U=124 mph (200 km/h), H=130 mph (210 km/h), V=149 mph (240 km/h), W=168 mph (270 km/h), Y=186 mph
(300 km/h), (Y)=vehicle's top speed (exceeds the "Y" rating).
Wheels and Tires
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MODEL Y Owner's Manual
