Automotive Technology/Tire Code

Tire identification diagram

• Tread width is usually in millimeters
• The aspect ratio is the sidewall divided by the tread width expressed as a percentage.
• They don't make passenger tires in the US that aren't radial.
• Rim size is usually in inches for unknown reasons.
• The load index refers to how much the weight the tire can handle
• The speed rating, shown as speed symbol, gives a maximum speed tolerance of the tire
• DOT tire code is a four digit code, 2 digit week and 2 digit year

The higher the aspect ratio, the easier the tire comes off the rim.

See Wheels