Tire Class - "P"
The first character(s) in a tire size designate
the tire's class. In this example, "P" indicates that the tire is a
passenger car tire. An "LT" before the tire size designates a light
truck tire, and no letter before the size indicates that it is a
European metric tire.
Section Width - "205"
A metric tire's section width is measured in
millimeters. This measurement is taken from sidewall to sidewall. In
this example, the section width of the tire 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.
Tire Construction - "R"
The "R" in this example indicates radial
tire construction.
Wheel Diameter - "16"
This indicates the wheel diameter in inches.
Diameter - "35"
The first number indicates the tire's
diameter in inches. In this example, the tire manufacturer has
determined that this is a 35" tire. However, actual measured overall
diameters vary from one manufacturer to the next.
Tire Width - "1250"
Standard tire width is indicated in inches with
the decimal point removed. Therefore, in this example, the number 1250
indicates that this tire is 12.5" wide.
Tire Construction - "R"
The "R" in this example indicates radial
tire construction.
Wheel Diameter - "17"
This indicates the wheel diameter in inches.
Plies - "E"
The last letter in a standard tire size indicates
the number of layers used in the construction of the tire. If there is
no letter, the tire has the standard 4 plies. A "C" indicates 6 plies, a
"D" indicates 8 plies, and an "E" indicates 10 plies. The higher the
number of plies in a tire, the stronger the tire is and the more air
pressure the tire can safely hold. Higher ply tires require more air
pressure to maintain proper wear.
Load Index & Speed Rating
Load Index - "92"
The load index indicates the maximum amount of weight a
tire can safely carry. Load index ranges from 0 to 279 and corresponds
with the load-carrying capacity of a tire. Passenger car tire load
indices typically range from 75 to 105. It is very important to maintain
the proper load index for your vehicle when replacing your tires. See
our load index chart for more information.
• See the Load Index Table
Speed Rating - "H"
A tire 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.
• Learn More About Speed Ratings
U.S. DOT & Safety Standard Markings
DOT
The "DOT" marking indicates that the tire meets or exceeds the U.S.
Department of Transportation's safety standard for tires.
Manufacturer Plant Code - "CC"
The first two letters following the DOT marking are codes to identify the
manufacturer of the tire and the manufacturing plant.
Tire Size - "9L"
The third and fourth characters following the DOT marking are codes
representing the tire size.
Brand Characteristics - "YYY"
The final three or four letters are codes representing other significant
characteristics of the tire as determined by the manufacturer.
Manufacture Week - "11"
The first pair of digits identifies the week the tire was
manufactured. In this case, the tire 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 tire was
manufactured, in this case 2005.
Treadwear, Traction & Temperature
Treadwear - "520"
The treadwear rating is a measurement of the tire'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 tire 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 tire's ability
to stop on a straight, wet surface under controlled conditions. It does
not indicate the tire'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 tire'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 - "635 kg [1400 lbs]"
This indicates the tire's maximum load-carrying capabilities when the tire
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 tire. It does
not indicate the manufacturer's recommended inflation pressure, nor does it
indicate the proper air pressure based on the vehicle the tire is mounted on.
This category is also based on NHTSA standards.
Note - Some tires are marked 'Extra Load', 'XL', or 'RF' (for reinforced). This
simply denotes that the tire's indicated maximum load and air pressure are higher
than a standard load tire.
Ply Construction
This indicates what materials are used in the tire's
plies, and the quantity of each type included.
Some tires indicate the direction of rotation on the sidewall, while
others indicate a specific side of the tire that is intended to face
outward from the vehicle. Another type of tire combines both
indications. It is important that these tires be mounted according to
the indicated instructions.
Directional Tires
Directional tires feature arrows on the sidewall that
indicate what direction the tire should rotate when the vehicle is
moving forward.
Asymmetrical Tires
Asymmetrical tires have the word "outside" labeled
on the side of the tire that should face outward from the vehicle.
Directional & Asymmetrical Tires Tires that are both directional and
asymmetrical will indicate what direction the tire must rotate, as well
as what side must face outward from the vehicle.
