Reading the sidewall of a tyre

HomeInfo CenterTyre InformationReading the sidewall of a tyre

Size (Metric)

Tyre Class – “P”

The first character(s) in a tyre size designate the tyre’s class. In this example, “P” indicates that the tyre is a passenger car tyre. An “LT” before the tyre size designates a light truck tyre, and no letter before the size indicates that it is a European metric tyre.

Section Width – “205”

A metric tyre’s section width is measured in millimeters. This measurement is taken from sidewall to sidewall. In this example, the section width of the tyre is 205mm.

Aspect Ratio – “65”

This number refers to the height of the sidewall. It is a percentage of the section width. In this example, 65 percent of the section width of 205mm equals 133.25.

Tyre Construction – “R”

The “R” in this example indicates radial tyre construction.

Wheel Diameter – “16”

This indicates the wheel diameter in inches.

Size (High Flotation)

Diameter – “35”

The first number indicates the tyre’s diameter in inches. In this example, the tyre manufacturer has determined that this is a 35″ tyre. However, actual measured overall diameters vary from one manufacturer to the next.

Tyre Width – “1250”

Standard tyre width is indicated in inches with the decimal point removed. Therefore, in this example, the number 1250 indicates that this tyre is 12.5″ wide.

Tyre Construction – “R”

The “R” in this example indicates radial tyre construction.

Wheel Diameter – “17”

This indicates the wheel diameter in inches.

Plies – “E”

This letter indicates the load carrying capacity of the tyre in terms of its construction. A “C” indicates the tyre has a 6-ply load carrying capacity. The tyre is not actually built with 6 plies, but contains one or two plies of equivalent strength. A “D” is an 8-ply rating, and an “E” is a 10-ply rating. If there is no letter, the tyre has a standard 4-ply rating.

Load Index & Speed Rating

Load Index – “92”

The load index indicates the maximum amount of weight a tyre can safely carry. Load index ranges from 0 to 279 and corresponds with the load-carrying capacity of a tyre. Passenger car tyre load indices typically range from 75 to 105. See our load index chart for more information.

See the Load Index Table

Speed Rating – “H”

A tyre receives its speed rating from the U.S. Government by meeting minimum standards for reaching and sustaining a specified speed. In general, a higher speed rating will result in better vehicle handling. See our speed rating page for more information and a list of the various speed ratings.

U.S. DOT & Safety Standard Markings


The “DOT” marking indicates that the tyre meets or exceeds the U.S. Department of Transportation’s safety standard for tyres.

Manufacturer Plant Code – “CC”

The first two letters following the DOT marking are codes to identify the manufacturer of the tyre and the manufacturing plant.

Tyre Size – “9L”

The third and fourth characters following the DOT marking are codes representing the tyre size.

Brand Characteristics – “YYY

The final three or four letters are codes representing other significant characteristics of the tyre as determined by the manufacturer.

Manufacture Week – “11”

The first pair of digits identifies the week the tyre was manufactured. In this case, the tyre was manufactured in the 11th week. The number 01 would indicate the first week of January, whereas the number 52 would indicate the last week of December.

Manufacture Year – “05”

The second pair of digits identifies the year that the tyre was manufactured, in this case 2005.

Treadwear, Traction & Temperature

Treadwear – “520”

The treadwear rating is a measurement of the tyre’s durability, but not the projected tread life. It is important to remember that road surfaces, driving habits, and other factors determine actual tread life. Each tyre manufacturer independently determines treadwear through their own tests. Treadwear is not based on any one industry or government standard.

Traction – “A”

The traction rating is a measurement of a tyre’s ability to stop on a straight, wet surface under controlled conditions. It does not indicate the tyre’s cornering ability on a wet surface or its traction on ice or snow. Traction grades include AA, A, B, and C, with AA being the highest grade available.

Temperature – “A”

The temperature rating is a measurement of a tyre’s resistance to heat generation under normal operating conditions at recommended inflation pressures. Temperature grades range from A to C, with A being highest rated and therefore most resistant to heat generation.

Maximum Load Limit & Air Pressure

Maximum Load Limit – “635 kg [1400 lbs]”

This indicates the tyre’s maximum load-carrying capabilities when the tyre is inflated to its maximum inflation pressure, as indicated on the sidewall. Max load is based on standards set by the National Highway Traffic Safety Administration (NHTSA).

Maximum Air Pressure – “300 kPa [44 psi]”

This indicates the maximum operating inflation pressure of the tyre. It does not indicate the manufacturer’s recommended inflation pressure, nor does it indicate the proper air pressure based on the vehicle the tyre is mounted on. This category is also based on NHTSA standards. Note – Some tyres are marked ‘Extra Load’, ‘XL’, or ‘RF’ (for reinforced). This simply denotes that the tyre’s indicated maximum load and air pressure are higher than a standard load tyre.

Ply Construction

This indicates what materials are used in the tyre’s plies, and the quantity of each type included.

Rotation Direction

Some tyres indicate the direction of rotation on the sidewall, while others indicate a specific side of the tyre that is intended to face outward from the vehicle. Another type of tyre combines both indications. It is important that these tyres be mounted according to the indicated instructions.

Directional Tyres

Directional tyres feature arrows on the sidewall that indicate what direction the tyre should rotate when the vehicle is moving forward.

Asymmetrical Tyres

Asymmetrical tyres have the word “outside” labeled on the side of the tyre that should face outward from the vehicle.

Directional & Asymmetrical Tyres

Tyres that are both directional and asymmetrical will indicate what direction the tyre must rotate, as well as what side must face outward from the vehicle.