There are many digits, numbers and symbols that may be found on a tyre's sidewall. Here are some examples and explanations of what they indicate.
Note
Be aware that the following tyre designations are only examples. Not all of these designations may be available for your tyres and there may be designations on your tyres which are not included here.
Tyre dimensions
All tyres have a designation of dimensions, such as: 265/40 R21 98 W.
265
Tyre width (mm).
40
Ratio between tyre wall height and tyre width (%).
R
Radial ply. The designation RF and symbol specify that the car is equipped with puncture-resistant tyres.
21
Rim diameter (inches).
98
Codes for the maximum permitted tyre load, Load Index.
W
Speed rating for maximum permitted speed, Speed Symbol.
Wheel rim dimensions
All wheel rims have a designation of dimensions, such as: 8J x 19 x 50.
8
Rim width (inches).
J
Rim flange profile.
19
Rim diameter (inches).
50
Offset in mm (distance from wheel centre to wheel contact surface against the hub).
Weather condition classification
Here are some classification examples. Weather capabilities can also be defined with certain symbols.
M+S or M/S
Mud and Snow.
AT
All Terrain.
AS
All Season.
Tyre age
DOT YLX2 0819
Tyre Identification Number or TIN. This information helps the tyre manufacturer identify tyres in the event of safety recalls.
The first two characters are the code for the plant where the tyre was manufactured.
The next two characters are the tyre's size code.
The last four digits specify the week and year the tyre was manufactured. For example, 0819 means that the tyre was manufactured during week 08, year 2019.
Any numbers or letters shown in between are market codes chosen by the manufacturer.
Max load and pressure
Max load 685 kg (1610 lbs).
Specifies the maximum load that the tyre can carry.
Max pressure 240 kPa (35 psi).
The maximum tyre pressure that the tyre should ever be subjected to. This limit is specified by the tyre manufacturer.
Minimum permitted load index and speed rating
Warning
The minimum permitted load index (LI) and speed rating (SS) for the tyres for each respective motor variant are shown in the specifications sections. If a tyre with too low a load index or speed rating is used, it may overheat and become damaged.
Type, materials and tyre rotation
P
Indicates that the tyre is for passenger vehicles.
States the number of cord layers or number of layers with rubber-coated fabric in the tyre's tread and sidewall. The tyre manufacturers must also state the layer materials used in the tyre and sidewall, which may be steel, nylon, polyester and certain other materials.
Arrow symbol
Tyres with a tread pattern designed to only turn in one direction have the direction of rotation marked with an arrow.
Classification of uniform tyre quality
Treadwear grade 200
The treadwear grade is a comparative rating based on the wear-rate of the tyre in a standardised test. A higher value is better.
Traction grade AA
The traction grade is based on standardised straight-ahead braking traction tests. The traction grades, from highest to lowest, are AA, A, B and C.
Temperature grade A
The temperature grade reflects the thermal performance of a tyre that is properly inflated and not overloaded. The temperature grades, from highest to lowest, are A, B and C.
