width BUICK ENVISION 2021 Owner's Manual

Buick E2UB-N Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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280 Vehicle Care
tires. If winter tires with a lower speed
rating are chosen, never exceed the tire's
maximum speed capability.
Tire Sidewall Labeling
Useful information about a tire is
molded into its sidewall. The examples
show a typical passenger vehicle tire
and a compact spare tire sidewall.
Passenger (P-Metric) Tire Example
(1) Tire Size:The tire size 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 in this section.
(2) 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.
(3) 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.
DOT Tire Date of Manufacture
:The last
four digits of the TIN indicate the tire
manufactured date. The first two digits
represent the week and the last two
digits, the year. For example, the third
week of the year 2020 would have a
4-digit DOT date of 0320. Week 01 is
the first full week (Sunday through
Saturday) of each year. (4) Tire Identification Number (TIN)
:
The letters and numbers following the
DOT (Department of Transportation)
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.
(5) Tire Ply Material
:The type of cord
and number of plies in the sidewall and
under the tread.
(6) Uniform Tire Quality Grading
(UTQG)
:Tire manufacturers are
required to grade tires based on three
performance factors: tread wear,
traction, and temperature resistance.
For more information see Uniform Tire
Quality Grading 0293.
(7) Maximum Cold Inflation Load
Limit
:Maximum load that can be
carried and the maximum pressure
needed to support that load.

Buick E2UB-N Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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Vehicle Care 281
Compact Spare Tire Example
(1) Tire Ply Material:The type of cord
and number of plies in the sidewall and
under the tread.
(2) Temporary Use Only
:The compact
spare tire or temporary use tire should
not be driven at speeds over 80 km/h
(50 mph). The compact spare tire is for
emergency use when a regular road tire
has lost air and gone flat. If the vehicle
has a compact spare tire, see Compact
Spare Tire 0301 and
If a Tire Goes Flat 0295. (3) Tire Identification Number (TIN)
:
The letters and numbers following the
DOT (Department of Transportation)
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.
(4) Maximum Cold Inflation Load
Limit
:Maximum load that can be
carried and the maximum pressure
needed to support that load.
(5) Tire Inflation
:The temporary use
tire or compact spare tire should be
inflated to 420 kPa (60 psi). For more
information on tire pressure and
inflation see Tire Pressure 0284.
(6) Tire Size
:A combination of letters
and numbers define a tire's width,
height, aspect ratio, construction type,
and service description. The letter “T”as
the first character in the tire size means
the tire is for temporary use only. (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
Tire Size
The example shows a typical passenger
vehicle tire size.
Passenger (P-Metric) Tire
(1) 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.

Buick E2UB-N Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
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282 Vehicle Care
(2) Tire Width:The 3-digit number
indicates the tire section width in
millimeters from sidewall to sidewall.
(3) Aspect Ratio
:A 2-digit number that
indicates the tire height-to-width
measurements. For example, if the tire
size aspect ratio is 75, as shown in
item (3) of the illustration, it would
mean that the tire's sidewall is
75 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.
(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 Pressure0284.
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 0193.
GAWR FRT
:Gross Axle Weight Rating
for the front axle. See Vehicle Load
Limits 0193.

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Vehicle Care 293
Uniform Tire Quality Grading
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 tires, compact 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.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
All Passenger Car Tires Must Conform to
Federal Safety Requirements In Addition
To These Grades.
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 one-half (1½)
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
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. Warning:
The traction grade assigned to this tire
is based on straight-ahead braking
traction tests, and does not include
acceleration, cornering, hydroplaning,
or peak traction characteristics.
Temperature
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

Buick E2UB-N Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
14583509) - 2021 - CRC - 1/8/21
294 Vehicle Care
corresponds to a level of performance
which all passenger car tires must meet
under the Federal Motor Safety
Standard No. 109. Grades B and A
represent higher levels of performance
on the laboratory test wheel than the
minimum required by law. Warning:
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 were aligned and
balanced at the factory to provide the
longest tire life and best overall
performance. Adjustments to wheel
alignment and tire balancing are not
necessary on a regular basis. Consider an
alignment check if there is unusual tire wear
or the vehicle is significantly pulling to one
side or the other. Some slight pull to the
left or right, depending on the crown of the
road and/or other road surface variationssuch as troughs or ruts, is normal. If the
vehicle is vibrating when driving on a
smooth road, the tires and wheels may
need to be rebalanced. See your dealer 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. Some aluminum
wheels can be repaired. See your dealer if
any of these conditions exist.
Your dealer will know the kind of wheel that
is needed.
Each new wheel should have the same
load-carrying capacity, diameter, width,
offset, and be mounted the same way as
the one it replaces.
Replace wheels, wheel bolts, wheel nuts,
or Tire Pressure Monitor System (TPMS)
sensors with new GM original equipment
parts.
{Warning
Using the wrong replacement wheels,
wheel bolts, or wheel nuts can be
dangerous. It could affect the braking and
handling of the vehicle. Tires can lose air,
and cause loss of control, causing a crash.
Always use the correct wheel, wheel
bolts, and wheel nuts for replacement.
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 or tire chain
clearance to the body and chassis.
Used Replacement Wheels
{Warning
Replacing a wheel with a used one is
dangerous. How it has been used or how
far it has been driven may be unknown.
It could fail suddenly and cause a crash.
When replacing wheels, use a new GM
original equipment wheel.