Knowing How To Read Tire Codes
No one takes for granted a tire on an automobile. However, there is a lot of information a customer needs to know about a tire.
It starts with the sidewall of the tire. There is a series of numbers and letters that one must know before buying an automobile or replacing the current set of tires. Here is a rundown of what those codes are:
P or T? The first letter of a tire size tells which application it will be used. P is for Passenger, while T is for truck.
A three digit number (for example: 225): That number is the width of the tire in millimeters.
The next two numbers (for example: 60): This is the size of the sidewall, also known as an Aspect ratio. It is the percentage of height of the sidewall is relationship with the width of the tread.
R? R means radial – which 99.9% of all of today’s tires are constructed. There is another letter that is added to this – the speed rating. A ZR code means that it has the highest speed rating available – well over 150MPH. Other speed ratings have limited top speed allowances.
The last two-digital number (for example: 17): This is the diameter of the inside of the tire corresponding to the diameter of the wheel. This is reflected in inches.
THE NEXT SET OF CODES
89V? This next set of numbers and letter(s) is called a service description. This tells the consumer the load (89) and speed (V) rating. This takes place of the speed rating used with the radial construction code.
M+S? This is unique since it is the only code allowable to distinguish a specific purpose for the tire. In this case, it is Mud and Snow rated. It tells the consumer that this is a tire that can be sued to get through mud or snow.
THE UNIFORM TIRE QUALITY GRADE
TREADWEAR: This code kicks off a series of information that the consumer might want to know about. On a scale of 100 to 700, this number represents the kind of treadwear to expect by relative percentage. This information is not available on winter tires, due to the nature of their soft compound construction.
TRACTION: Four grades are used to determine the traction capability of the tire – AA, A, B, C. AA is the best rating possible.
TEMPERATURE: This grade determines the level of heat build up resistance for this tire, in correlation to speed levels. Grades used are A, B and C – with A being best.
NOTES: This restates the speed rating to tie back to the rest of the Uniform Tire Quality Grades.
TIRE AGE AND DATE OF MANUFACTURE
There are twelve letters and numbers that are found close to the rim of the tire. It always starts with DOT – the U.S. Department of Transportation, that is. It is simply a construction code, until the last four digits. Those are the most important since it states the date of manufacture for the tire. For example: 0315 – that is the third week of 2015 = 03 as in third week, 15 = 2015.
There is a lot of confusion in these codes. If more detective work is needed, the service department at Volkswagen Van Nuys can explain further when tires are being inspected or replaced. Don’t forget, we also sell and install new tires for your vehicle, too!