Chevrolet Corvette Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11374030) - 2018 - crc - 3/29/17
260 Vehicle Care
(3) 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.
(4) 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.
(5) Rim Diameter
:Diameter of
the wheel in inches.
(6) 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.
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
0 263.
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.
Chevrolet Corvette Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
11374030) - 2018 - crc - 3/29/17
274 Vehicle Care
Caution
The wrong wheel can also cause
problems with bearing life, brake
cooling, speedometer or
odometer calibration, headlamp
aim, bumper height, vehicle
ground clearance, and tire
clearance to the body and
chassis.
Tightening Wheel Lug Nuts
{Warning
Never use oil or grease on studs
or the threads of the wheel nuts.
The wheel nuts might come loose
and the wheel could fall off,
causing a crash.
{Warning
Incorrect wheel nuts or improperly
tightened wheel nuts can cause
the wheel to become loose and
even come off. This could lead to
a crash. Be sure to use the
correct wheel nuts. If you have to
replace them, be sure to get new
GM original equipment
wheel nuts.
Caution
Improperly tightened wheel nuts
can lead to brake pulsation and
rotor damage. To avoid expensive
brake repairs, evenly tighten the
wheel nuts in the proper
sequence and to the proper
torque specification.
Tighten the wheel lug nuts firmly in
a crisscross sequence. See
Capacities and Specifications 0313.
Tire Chains
{Warning
Do not use tire chains. There is
not enough clearance. Tire chains
used on a vehicle without the
proper amount of clearance can
cause damage to the brakes,
suspension, or other vehicle
parts. The area damaged by the
tire chains could cause loss of
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