Buick Regal: Tire Sidewall Labeling
Useful information about a tire is
molded into its sidewall. The
examples show a typical
passenger vehicle tire and a
compact spare tire sidewall.
Passenger (P-Metric) Tire Example
- Tire Size : The tire size is a
combination of letters and
numbers used to define a
particular tire's width, height,
aspect ratio, construction type,
and service description. See the
"Tire Size" illustration later in this
section.
- TPC Spec (Tire
Performance Criteria
Specification) : Original
equipment tires designed to
GM's specific tire performance
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet or
exceed all federal safety
guidelines.
- DOT (Department of
Transportation) : The
Department of Transportation
(DOT) code indicates that the
tire is in compliance with the
U.S. Department of
Transportation Motor Vehicle
Safety Standards.
DOT Tire Date of
Manufacture : The last four
digits of the TIN indicate the tire
manufactured date. The first two
digits represent the week (01-
52) and the last two digits, the
year. For example, the third
week of the year 2010 would
have a four-digit DOT date
of 0310.
- Tire Identification Number
(TIN) : The letters and numbers
following the DOT (Department
of Transportation) code are the Tire Identification Number (TIN).
The TIN shows the
manufacturer and plant code,
tire size, and date the tire was
manufactured. The TIN is
molded onto both sides of the
tire, although only one side may
have the date of manufacture.
- Tire Ply Material : The type
of cord and number of plies in
the sidewall and under the tread.
- Uniform Tire Quality
Grading (UTQG) : Tire
manufacturers are required to
grade tires based on three
performance factors: treadwear,
traction, and temperature
resistance. For more information
see Uniform Tire Quality
Grading.
- Maximum Cold Inflation
Load Limit : Maximum load that
can be carried and the
maximum pressure needed to
support that load.
Compact Spare Tire Example
- Tire Ply Material : The type
of cord and number of plies in
the sidewall and under the tread.
- Temporary Use Only : The
compact spare tire or temporary
use tire should not be driven at
speeds over 80 km/h (50 mph).
The compact spare tire is for
emergency use when a regular
road tire has lost air and gone
flat. If the vehicle has a compact
spare tire.
- Tire Identification Number
(TIN) : The letters and numbers
following the DOT (Department
of Transportation) code are the
Tire Identification Number (TIN).
The TIN shows the
manufacturer and plant code,
tire size, and date the tire was
manufactured. The TIN is
molded onto both sides of the
tire, although only one side may
have the date of manufacture.
- Maximum Cold Inflation
Load Limit : Maximum load that
can be carried and the
maximum pressure needed to
support that load.
- Tire Inflation : The
temporary use tire or compact
spare tire should be inflated to
420 kPa (60 psi).
- Tire Size : A combination of
letters and numbers define a
tire's width, height, aspect ratio,
construction type, and service
description. The letter T as the
first character in the tire size
means the tire is for temporary
use only.
- TPC Spec (Tire
Performance Criteria
Specification) : Original
equipment tires designed to
GM's specific tire performance
criteria have a TPC specification
code molded onto the sidewall.
GM's TPC specifications meet or
exceed all federal safety
guidelines.
Tire Designations
Tire Size
The following is an example of a
typical passenger vehicle
tire size.
- Passenger (P-Metric) Tire :
The United States version of a
metric tire sizing system. The
letter P as the first character in
the tire size means a passenger
vehicle tire engineered to
standards set by the U.S. Tire
and Rim Association.
- Tire Width : The three-digit
number indicates the tire section
width in millimeters from
sidewall to sidewall.
- Aspect Ratio : A two-digit
number that indicates the tire
height-to-width measurements.
For example, if the tire size
aspect ratio is 60, as shown in
item 3 of the illustration, it would
mean that the tire's sidewall is
60 percent as high as it is wide.
- Construction Code : A letter
code is used to indicate the type
of ply construction in the tire.
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.
- Rim Diameter : Diameter of
the wheel in inches.
- Service Description : These
characters represent the load
index and speed rating of the
tire. The load index represents
the load carrying capacity a tire
is certified to carry. The speed
rating is the maximum speed a
tire is certified to carry a load.
READ NEXT:
Air Pressure : The amount of
air inside the tire pressing
outward on each square inch of the tire. Air pressure is
expressed in kPa (kilopascal)
or psi (pounds per square inch).
Accessory Weight : Th
Tires need the correct amount of
air pressure to operate
effectively.
Caution:
Neither tire underinflation nor
overinflation is good.
Underinflated tires, or tires
that do not have enough air,
can r
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your tires and
transmit tire pressure readings to a
SEE MORE:
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strategy Based
Diagnosis
An overview of each diagnostic category can be found here: Diagnostic
Proced
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Refer to Diagnostic System
Check - Vehicle
Review the description of Strategy Based Diagnosis: Refer to Strategy
Based Diagnosis
An overview of each diagnostic category can be found here: R