2010 GMC YUKON DENALI width

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.
2-39

Driving Across an Incline
An off-road trail will probably go across the incline of a
hill. 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 down
might be too steep to drive across. When going
straight up or down a hill, the length of the wheel
base—the distance from the front wheels to the
rear wheels —reduces the likelihood the vehicle
will tumble end over end. But when driving across
an incline, the narrower track width —the distance
between the left and right wheels —might not
prevent the vehicle from tilting and rolling over.
Driving across an incline puts more weight on the
downhill wheels which could cause a downhill slide
or a rollover.
.Surface conditions can be a problem. Loose
gravel, muddy spots, or even wet grass can cause
the tires to slip sideways, downhill. If the vehicle
slips sideways, it can hit something that will
trip it —a rock, a rut, etc. —and roll over.
.Hidden obstacles can make the steepness of the
incline even worse. If you drive across a rock with
the uphill wheels, or if the downhill wheels drop
into a rut or depression, the vehicle can tilt
even more.
For these reasons, carefully consider whether to try to
drive across an incline. Just because the trail goes
across 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, turn
downhill. This should help straighten out the vehicle and
prevent the side slipping. The best way to prevent this
is to “walk the course” first, so you know what the
surface is like before driving it.
5-21

To adjust the vertical aim:1. Open the hood. See Hood Release on page 6‑12
2. Locate the aim dot on the lens of the low‐beam
headlamp.
3. Record the distance from the ground to the aim dot on the low‐beam headlamp.
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 the width of the vehicle at the height of the mark in
Step 4.
Notice: Do not cover a headlamp to improve beam
cut-off when aiming. Covering a headlamp may
cause excessive heat build-up which may cause
damage to the headlamp.
6. Turn on the low-beam headlamps and place a piece of cardboard or equivalent in front of the
headlamp not being adjusted. This allows only the
beam of light from the headlamp being adjusted to
be seen on the flat surface.
6-51

20‐Inch Tires
If your vehicle has the optional 20‐inch
P275/55R20 size tires, they are classified as
touring tires and are designed for on road use.
The low‐profile, wide tread design is not
recommended for off‐road driving. SeeOff-Road
Driving
on page 5‑12, for additional information.
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.
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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.
6-60

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. See Inflation - Tire Pressure
on
page 6‑64
.
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 Vehicle
on page 5‑31.
GAWR FRT
:Gross Axle Weight Rating for the
front axle. See Loading the Vehicle
on page 5‑31.
GAWR RR
:Gross Axle Weight Rating for the rear
axle. See Loading the Vehicle
on page 5‑31.
6-61

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 and
balanced carefully at the factory to give you the longest
tire life and best overall performance. Adjustments to
wheel alignment and tire balancing will not be
necessary on a regular basis. However, if you notice
unusual tire wear or your vehicle pulling to one side or
the other, the alignment might need to be checked.
If you notice your vehicle vibrating when driving on a
smooth road, the tires and wheels might need to be
rebalanced. See your dealer/retailer for proper
diagnosis.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly
rusted or corroded. If wheel nuts keep coming loose,
the wheel, wheel bolts, and wheel nuts should be
replaced. If the wheel leaks air, replace it (except some
aluminum wheels, which can sometimes be repaired).
See your dealer/retailer if any of these conditions exist.
Your dealer/retailer will know the kind of wheel
you need.
Each new wheel should have the same load-carrying
capacity, diameter, width, offset, and be mounted the
same way as the one it replaces.
6-77