Tyre sidewall labeling
This information identifies and describes the fundamental characteristics of the tyre and provides the Tyre Identification Number (TIN) for safety standard certification.
 N_CT25_A12_017_A |
The TIN can be used to identify the tyre in case of a recall.
1. Manufacturer or brand name
The sidewall shows the manufacturer or brand name.
2. Tyre size designation
A tyre’s sidewall is marked with a tyre size designation. You will need this information when selecting replacement tyres for your vehicle. The following example explains what the letters and numbers in the tyre size designation mean.
(These numbers are provided as an example only; your tyre size designation could vary depending on your vehicle.)
Example tyre size designation:
P255/45R20 105V
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P: Applicable vehicle type (tyres marked with the prefix “P” are intended for use on passenger vehicles or light trucks; however, not all tyres have this marking).
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255: Tyre width in millimeters.
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45: Aspect ratio (the tyre’s section height as a percentage of its width).
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R: Tyre construction code (Radial).
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20: Rim diameter in inches.
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105: Load Index (a numerical code associated with the maximum load the tyre can carry).
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V: Speed Rating Symbol. See the speed rating chart in this section for additional information.
Wheels are also marked with important information that you need if you ever have to replace one. The following example explains what the letters and numbers in the wheel size designation mean.
Example wheel size designation:
8.5JX20
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8.5: Rim width in inches.
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J: Rim contour designation.
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20: Rim diameter in inches.
The following chart lists many of the different speed ratings that are currently used for passenger vehicle tyres. The speed rating is part of the tyre size designation marked on the sidewall of the tyre. This symbol corresponds to that tyre’s designed maximum safe operating speed.
|
Speed Rating Symbol |
Maximum Speed |
|---|---|
|
S |
180 km/h (112 mph) |
|
T |
190 km/h (118 mph) |
|
H |
210 km/h (130 mph) |
|
V |
240 km/h (149 mph) |
|
W |
270 km/h (168 mph) |
|
Y |
300 km/h (186 mph) |
3. Checking tyre life
Any tyres that are over 6 years old, based on the manufacturing date, should be replaced with new ones. You can find the manufacturing date on the tyre sidewall (possibly on the inside of the wheel) displayed as part of the DOT code. The DOT code consists of a series of numbers and English letters on a tyre. The manufacturing date is designated by the last 4 digits (characters) of the DOT code.
DOT: XXXX XXXX OOOO
The first part of the DOT code contains the plant code number, tyre size, and tread pattern, and the last four numbers indicate week and year manufactured.
For example:
DOT XXXX XXXX 1626 means that the tyre was produced in the 16th week of 2026.
Tyre age
Replace tyres within the recommended time frame. Failure to replace tyres as recommended can result in sudden tyre failure, which could lead to a loss of vehicle control and an accident.
4. Tyre ply composition and material
Tyre ply means the number of layers (or plies) of rubber-coated fabric in the tyre. Tyre manufacturers must list the materials in the tyre, which include steel, nylon, polyester, and others. The letter R means radial ply construction, the letter D means diagonal or bias ply construction, and the letter B means belted-bias ply construction.
5. Maximum Inflation Pressure
This number is the greatest amount of air pressure that should be put into the tyre. Do not exceed the maximum inflation pressure. Refer to Tyres and wheels for the recommended inflation pressure.
6. Maximum load rating
This number is the maximum load in kilograms and pounds that the tyre can carry. When replacing the tyres on the vehicle, always use a tyre that has the same load rating as the factory-installed tyre.
7. Uniform Tyre Quality Grading
Quality grades can be found where applicable on the tyre sidewall between tread shoulder and maximum section width.
For example:
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Treadwear 200
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Traction AA
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Temperature A
Tyres degrade over time, even when you are not using them. Regardless of the remaining tread, we recommend that you replace the tyres after approximately 6 years of normal service. Heat from hot climates or frequent high loading conditions can accelerate the aging process.
The tread wear grade is a comparative rating based on the wear rate of the tyre when tested under controlled conditions on a specified government test course. For example, a tyre graded 150 would wear 1½ times as well on the government test course as a tyre graded 100.
The relative performance of tyres depends on the actual conditions of their use. Performance may depart significantly from the norm due to variations in driving habits, service practices, and differences in road characteristics and climate.
Tread wear grades are molded on the sidewalls of passenger vehicle tyres. The tyres available as standard or optional equipment on your vehicle may vary with respect to grade.
The traction grades from highest to lowest are AA, A, B, and C. These grades represent the tyre’s ability to stop on wet pavement as measured under controlled conditions on specified government test surfaces of asphalt and concrete. A tyre marked C may have poor traction performance.
The traction grade assigned to this tyre is based on straight-ahead braking traction tests and does not include acceleration, turning, hydroplaning, or peak traction characteristics.
The temperature grades from highest to lowest are A, B, and C, representing the tyre’s resistance to the generation of heat and its ability to dissipate heat when tested under controlled conditions on a specified indoor laboratory test wheel.
Sustained high temperature can cause the material of the tyre to degenerate and reduce the life of the tyre, and excessive temperature can lead to sudden tyre failure. Grades B and A represent higher levels of performance on the laboratory test wheel than the minimum required by law.