Q: What is wrong with this?
A:The belt is twisted across the body.
{WARNING:
You can be seriously injured by a twisted belt. In a
crash, you would not have the full width of the belt
to spread impact forces. If a belt is twisted, make
it straight so it can work properly, or ask your
dealer/retailer to fix it.
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Driving Across an Incline
An off-road trail will probably go across the incline of ahill. To decide whether to try to drive across the incline,consider the following:
{WARNING:
Driving across an incline that is too steep
will make your vehicle roll over. You could be
seriously injured or killed. If you have any doubt
about the steepness of the incline, do not drive
across it. Find another route instead.
.A hill that can be driven straight up or downmight be too steep to drive across. When goingstraight up or down a hill, the length of the wheelbase—the distance from the front wheels to therear wheels—reduces the likelihood the vehiclewill tumble end over end. But when driving acrossan incline, the narrower track width—the distancebetween the left and right wheels—might notprevent the vehicle from tilting and rolling over.Driving across an incline puts more weight on thedownhill wheels which could cause a downhill slideor a rollover.
.Surface conditions can be a problem. Loosegravel, muddy spots, or even wet grass cancause the tires to slip sideways, downhill. If thevehicle slips sideways, it can hit something thatwill trip it—a rock, a rut, etc.—and roll over.
.Hidden obstacles can make the steepness of theincline even worse. If you drive across a rock withthe uphill wheels, or if the downhill wheels dropinto a rut or depression, the vehicle can tilteven more.
For these reasons, carefully consider whether to try todrive across an incline. Just because the trail goesacross the incline does not mean you have to drive it.The last vehicle to try it might have rolled over.
If you feel the vehicle starting to slide sideways, turndownhill. This should help straighten out the vehicle andprevent the side slipping. The best way to prevent thisis to“walk the course”first, so you know what thesurface is like before driving it.
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4. At a wall, measure from the ground upward (A) tothe recorded distance from Step 3 and mark it.
5. Draw or tape a horizontal line (B) on the wall thewidth of the vehicle at the height of the mark inStep 4.
Notice:Do not cover a headlamp to improve beamcut-off when aiming. Covering a headlamp maycause excessive heat build-up which may causedamage to the headlamp.
6. Turn on the low-beam headlamps and place apiece of cardboard or equivalent in front of theheadlamp not being adjusted. This allows only thebeam of light from the headlamp being adjusted tobe seen on the flat surface.
7. Locate the vertical headlamp aiming screws, whichare under the hood near each headlamp assembly.
The adjustment screw can be turned with aE8 Torx®socket.
8. Turn the vertical aiming screw until the headlampbeam is aimed to the horizontal tape line. Turn itclockwise or counterclockwise to raise or lower theangle of the beam.
7-53
Tire Sidewall Labeling
Useful information about a tire is molded into the
sidewall. The following illustration is an example
of a typical P!Metric tire sidewall.
Passenger (P!Metric) Tire
(A) Tire Size:The tire size code 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 for more detail.
(B) 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.
(C) 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.
(D) Tire Identification Number (TIN):The letters
and numbers following DOT 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.
(E) Tire Ply Material:The type of cord and
number of plies in the sidewall and under the
tread.
(F) 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,
seeUniform Tire Quality Gradingon page 7!76.
7-60
(G) Maximum Cold Inflation Load Limit:
Maximum load that can be carried and the
maximum pressure needed to support that load.
For information on recommended tire pressure
seeInflation - Tire Pressureon page 7!65and
Loading the Vehicleon page 6!32.
Tire Size
The following examples show the different parts of
a tire size.
Passenger (P!Metric) Tire
(A) 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.
(B) Tire Width:The three!digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio:A two!digit number that
indicates the tire height!to!width measurements.
For example, if the tire size aspect ratio is 75, as
shown in item C of the light truck (LT!Metric) tire
illustration, it would mean that the tire's sidewall is
75% as high as it is wide.
(D) 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.
(E) Rim Diameter:Diameter of the wheel in
inches.
(F) Service Description:These characters
represent the load index and speed rating of the
tire. The load index represents the load carry
capacity a tire is certified to carry. The speed
rating is the maximum speed a tire is certified to
carry a load.
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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 pounds per square
inch (psi) or kilopascal (kPa).
Accessory Weight:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, 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 that is
located 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 pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat
from driving. SeeInflation - Tire Pressureon
page 7!65.
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
Loading the Vehicleon page 6!32.
GAWR FRT:Gross Axle Weight Rating for the
front axle. SeeLoading the Vehicleon page 6!32.
GAWR RR:Gross Axle Weight Rating for the rear
axle. SeeLoading the Vehicleon page 6!32.
7-62
Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA
Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration (NHTSA), which
grades tires by treadwear, traction, and
temperature performance. This applies only to
vehicles sold in the United States. The grades are
molded on the sidewalls of most passenger car
tires. The Uniform Tire Quality Grading (UTQG)
system does not apply to deep tread, winter-type
snow tires, space-saver, or temporary use spare
tires, tires with nominal rim diameters of
10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
While the tires available on General Motors
passenger cars and light trucks may vary with
respect to these grades, they must also conform
to federal safety requirements and additional
General Motors Tire Performance Criteria (TPC)
standards.
Treadwear
The treadwear grade is a comparative rating
based on the wear rate of the tire when tested
under controlled conditions on a specified
government test course. For example, a tire
graded 150 would wear one and a half (1.5) times
as well on the government course as a tire
graded 100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart significantly from the
norm due to variations in driving habits, service
practices, and differences in road characteristics
and climate.
Traction–AA, A, B, C
The traction grades, from highest to lowest, are
AA, A, B, and C. Those grades represent the
tire's ability to stop on wet pavement as measured
under controlled conditions on specified
government test surfaces of asphalt and concrete.
A tire marked C may have poor traction
performance.
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Temperature–A, B, C
The temperature grades are A (the highest),
B, and C, representing the tire's resistance to the
generation of heat and its ability to dissipate heat
when tested under controlled conditions on a
specified indoor laboratory test wheel. Sustained
high temperature can cause the material of the
tire to degenerate and reduce tire life, and
excessive temperature can lead to sudden tire
failure. The grade C corresponds to a level of
performance which all passenger car tires must
meet under the Federal Motor Vehicle Safety
Standard No. 109. Grades B and A represent
higher levels of performance on the laboratory test
wheel than the minimum required by law. It should
be noted that the temperature grade for this tire is
established for a tire that is properly inflated and
not overloaded. Excessive speed, underinflation,
or excessive loading, either separately or in
combination, can cause heat buildup and possible
tire failure.
Wheel Alignment and Tire Balance
The tires and wheels on your vehicle were aligned andbalanced carefully at the factory to give you the longesttire life and best overall performance. Adjustments towheel alignment and tire balancing will not benecessary on a regular basis. However, if you noticeunusual tire wear or your vehicle pulling to one side orthe other, the alignment might need to be checked.If you notice your vehicle vibrating when driving on asmooth road, the tires and wheels might need to berebalanced. See your dealer/retailer for properdiagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked, or badlyrusted or corroded. If wheel nuts keep coming loose,the wheel, wheel bolts, and wheel nuts should bereplaced. If the wheel leaks air, replace it (except somealuminum wheels, which can sometimes be repaired).See your dealer/retailer if any of these conditions exist.
Your dealer/retailer will know the kind of wheelyou need.
Each new wheel should have the same load-carryingcapacity, diameter, width, offset, and be mounted thesame way as the one it replaces.
7-77