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first character in the tire size
means the tire is for temporary use only.
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.
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.
width in millimeters from sidewall to sidewall.
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.
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.
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.
Tire Terminology and Definitions
on each square inch of the tire. Air pressure is expressed in kPa (kilopascal) or psi (pounds per
square inch).
Some examples of optional accessories are automatic
transmission, power windows,
power seats, and air conditioning.
354 VEHICLE CARE
cords between the plies and the tread. Cords may be made from steel or other reinforcing
materials.
alternate angles less than
90 degrees to the centerline of the tread.
Tire Pressure 0 356.
optional equipment including the maximum capacity of fuel, oil, and coolant, but without passengers
and cargo.
signifying that the tire is in compliance with the U.S.
Department of Transportation (DOT) Motor Vehicle Safety
Standards. The DOT code includes the Tire Identification Number
(TIN), an alphanumeric designator which can also identify the tire
manufacturer, production plant, brand, and date of production.
Vehicle Load Limits 0 211.
Vehicle Load Limits 0 211.
The side of an asymmetrical tire that must always face outward
when mounted on a vehicle.
vehicles.
corresponds to the load carrying capacity of a tire.
The maximum air pressure to
which a cold tire can be inflated.
The maximum air pressure is molded onto the sidewall.
permissible inflation pressure for that tire.
weight.
VEHICLE CARE 355
68 kg (150 lb). See Vehicle Load Limits 0 211.
Designated seating positions.
outward when mounted on a
vehicle. The side of the tire that
contains a whitewall, bears white lettering, or bears manufacturer, brand, and/or model name
molding that is higher or deeper than the same moldings on the other sidewall of the tire.
light duty trucks and multipurpose vehicles.
pressure as shown on the tire
placard.
See Tire Pressure 0 356 and Vehicle Load Limits 0 211.
and upon which the tire beads are seated.
tire can operate.
the tire and the road surface. The amount of grip provided.
bars, that show across the tread of
a tire when only 1.6 mm (1/16 in) of tread remains. See When It Is
Time for New Tires 0 363.
information system that provides consumers with ratings for a tire's traction, temperature, and
treadwear. Ratings are determined by tire manufacturers using
government testing procedures. The ratings are molded into the sidewall of the tire. See Uniform Tire Quality Grading 0 365.
positions multiplied by
68 kg (150 lb) plus the rated cargo
load. See Vehicle Load Limits 0 211.
weight, occupant weight, and cargo weight.