Tire Designations; Tire Terminology And Definitions - Chevrolet Spark 2022 Owner's Manual

156 Vehicle Care
(7) 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

E.g. 185/65 R 15 91 H
185 : Tire width, mm
65 : Cross-section ratio (tire height to tire
width), %
R : Belt type: Radial
RF : Type: RunFlat
15 : Wheel diameter, inches
91 : Load index e.g. 91 is equivalent to
615 kg
H : Speed code letter
Speed code letter:
Q : Up to 160 km/h
S : Up to 180 km/h
T : Up to 190 km/h
H : Up to 210 km/h
V : Up to 240 km/h
W : Up to 270 km/h
Directional tires
Directional tires must be mounted so that
they rotate in the correct direction. The
proper rotation direction is indicated by a
symbol (e.g. an arrow) on the sidewall.

Tire Terminology and Definitions

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 : The combined weight of
optional accessories. Some examples of
optional accessories are automatic
transmission, power windows, power seats,
and air conditioning.
Aspect Ratio : The relationship of a tire's
height to its width.
Belt : A rubber coated layer of cords
between the plies and the tread. Cords may
be made from steel or other reinforcing
materials.
Bead : The tire bead contains steel wires
wrapped by steel cords that hold the tire
onto the rim.
Bias Ply Tire : A pneumatic tire in which the
plies are laid at alternate angles less than
90 degrees to the centerline of the tread.
Cold Tire Pressure : The amount of air
pressure in a tire, measured in kPa
(kilopascal) or psi (pounds per square inch)
before a tire has built up heat from driving.
See Tire Pressure 0 158.
Curb Weight : The weight of a motor
vehicle with standard and optional
equipment including the maximum capacity
of fuel, oil, and coolant, but without
passengers and cargo.
DOT Markings : A code molded into the
sidewall of a tire 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.
GVWR : Gross Vehicle Weight Rating. See
Vehicle Load Limits 0 113.
GAWR FRT : Gross Axle Weight Rating for
the front axle. See Vehicle Load Limits 0 113.
GAWR RR : Gross Axle Weight Rating for the
rear axle. See Vehicle Load Limits 0 113.