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 6-67.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 6-70.
Vehicle Capacity Weight
:
The number of
designated seating positions multiplied by 150 lbs
(68 kg) plus the rated cargo load. SeeLoading
the Vehicle on page 5-20.
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 inflation pressure. See “Tire
and Loading Information Label” underLoading the
Vehicle on page 5-20.
6-58
Inflation - Tire PressureTires need the correct amount of air pressure to
operate effectively.
Notice:Do not let anyone tell you that
under-inflation or over-inflation is all right.
It is not. If your tires do not have enough air
(under-inflation), you can get the following:•
Too much flexing
•
Too much heat
•
Tire overloading
•
Premature or irregular wear
•
Poor handling
•
Reduced fuel economy
If your tires have too much air (over-inflation),
you can get the following:
•
Unusual wear
•
Poor handling
•
Rough ride
•
Needless damage from road hazardsA vehicle specific Tire and Loading Information
label is attached to your vehicle. This label shows
your vehicle’s original equipment tires and the
correct inflation pressures for your tires when they
are cold. The recommended cold tire inflation
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,
seeLoading the Vehicle on page 5-20. 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 CheckCheck 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 6-86.
6-59
Temperature – A, B, CThe 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 BalanceThe 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 ReplacementReplace 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.
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