Page 404 of 510
Intended Outboard Sidewall:The side of an
asymmetrical tire, that must always face outward
when mounted on a vehicle.
Kilopascal (kPa):The metric unit for air pressure.
Light Truck (LT-Metric) Tire:A tire used on
light duty trucks and some multipurpose passenger
vehicles.
Load Index:An assigned number ranging from
1 to 279 that corresponds to the load carrying
capacity of a tire.
Maximum In ation Pressure:The maximum air
pressure to which a cold tire may be in ated.
The maximum air pressure is molded onto
the sidewall.
Maximum Load Rating:The load rating for a tire
at the maximum permissible in ation pressure
for that tire.
Maximum Loaded Vehicle Weight:The sum of
curb weight, accessory weight, vehicle capacity
weight, and production options weight.Normal Occupant Weight:The number of
occupants a vehicle is designed to seat multiplied
by 150 lbs (68 kg). SeeLoading Your Vehicle
on page 324.
Occupant Distribution:Designated seating
positions.
Outward Facing Sidewall:The side of an
asymmetrical tire that has a particular side that
faces outward when mounted on a vehicle.
The side of the tire that contains a whitewall, bears
white lettering, or bears manufacturer, brand,
and/or model name molding that is higher
or deeper than the same moldings on the other
sidewall of the tire.
Passenger (P-Metric) Tire:A tire used on
passenger cars and some light duty trucks and
multipurpose vehicles.
Recommended In ation Pressure:Vehicle
manufacturer’s recommended tire in ation
pressure as shown on the tire placard. See
In ation - Tire Pressure on page 406andLoading
Your Vehicle on page 324.
404
Page 405 of 510
Radial Ply Tire:A pneumatic tire in which the
ply cords that extend to the beads are laid at
90 degrees to the centerline of the tread.
Rim:A metal support for a tire and upon which
the tire beads are seated.
Sidewall:The portion of a tire between the tread
and the bead.
Speed Rating:An alphanumeric code assigned
to a tire indicating the maximum speed at
which a tire can operate.
Traction:The friction between the tire and the
road surface. The amount of grip provided.
Tread:The portion of a tire that comes into
contact with the road.
Treadwear Indicators:Narrow bands, sometimes
called wear bars, that show across the tread of
a tire when only 1/16 inch (1.6 mm) of tread
remains. SeeWhen It Is Time for New Tires on
page 409.UTQGS (Uniform Tire Quality Grading
Standards):A tire information system that
provides consumers with ratings for a tire’s
traction, temperature, and treadwear. Ratings are
determined by tire manufacturers using
government testing procedures. The ratings are
molded into the sidewall of the tire. SeeUniform
Tire Quality Grading on page 412.
Vehicle Capacity Weight:The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. SeeLoading
Your Vehicle on page 324.
Vehicle Maximum Load on the Tire:Load on an
individual tire due to curb weight, accessory
weight, occupant weight, and cargo weight.
Vehicle Placard:A label permanently attached to
a vehicle showing the vehicle’s capacity weight
and the original equipment tire size and
recommended in ation pressure. See “Tire and
Loading Information Label” underLoading
Your Vehicle on page 324.
405
Page 406 of 510
In ation - Tire Pressure
Tires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-in ation or over-in ation is all right. It is
not. If your tires do not have enough air
(under-in ation), you can get the following:
Too much exing
Too much heat
Tire overloading
Premature or irregular wear
Poor handling
Reduced fuel economy
If your tires have too much air (over-in ation),
you can get the following:
Unusual wear
Poor handling
Rough ride
Needless damage from road hazardsA Tire and Loading Information label is attached to
the vehicle’s center pillar (B-pillar). This label
shows your vehicle’s original equipment tires and
the correct in ation pressures for your tires
when they are cold. The recommended cold tire
in ation pressure, shown on the label, is the
minimum amount of air pressure needed to
support your vehicle’s maximum load carrying
capacity.
For additional information regarding how much
weight your vehicle can carry, and an example of
the Tire and Loading Information label, see
Loading Your Vehicle on page 324. How you load
your vehicle affects vehicle handling and ride
comfort. Never load your vehicle with more weight
than it was designed to carry.
When to Check
Check your tires once a month or more. Do not
forget to check the compact spare tire, it should be
at 60 psi (420 kPa). For additional information
regarding the compact spare tire, seeCompact
Spare Tire on page 434.
406
Page 414 of 510
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 may need to be checked. If you notice
your vehicle vibrating when driving on a smooth
road, your tires and wheels may 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.
If you need to replace any of your wheels,
wheel bolts, or wheel nuts, replace them only with
new GM original equipment parts. This way,
you will be sure to have the right wheel, wheel
bolts, and wheel nuts for your vehicle.
414