Chevrolet 1980 Light Duty Truck Service Manual page 305

attaching part in that they could affect the performance of vital
components and systems, and/or could result in major repair expense.
They must be replaced with one of the same part number or with an
equivalent part if replacement becomes necessary. Do not use a
replacement part of lesser quality or substitute design. Torque values
must be used as specified during reassembly to assure proper retention
of this part.
General Description........................................................3E-1
Replacement Tires.......................................................3E-1
Metric Tires................................................................. ..3E-1
Replacement Wheels.....................................................3E-2
Certification Label........................................................3E-2
Service Operations........................................................ ..3E-3
Tire Inspection and Rotation......................................3E-3
GENERAL DESCRIPTION
The factory installed tires and wheels are designed to
operate satisfactorily with loads up to and including the full
rated load capacity when inflated to the recommedned
inflation pressures.
Correct tire pressures and driving techniques have an
important influence on tire life. Heavy cornering,
excessively rapid acceleration, and unnecessary sharp
braking increase tire wear.
REPLACEMENT TIRES
CAUTION: Do not mix different types of
tires on the same vehicle such as radial,
bias, and bias-belted
emergencies, because vehicle handling
may be seriously affected and may result
in loss of control.
Some truck-type tires and most passenger-car-type
radial tires have a TPC Spec. No. (Tire Performance
Criteria Specification Number) molded into the tire sidewall
near the tire size marking. This shows that the tire meets
rigid size and performance standards which were developed
for the vehicle. The TPC Spec. No. assures a proper
combination of endurance, load capacity, handling, and
traction on wet, dry and snow covered surfaces. When
replacing tires with tires having the same TPC Spec. No.,
tires will be compatible with the vehicle. When replacing
tires with those not having a TPC spec, use the same size,
load range, and construction type (bias, bias-belted, or
radial) as the original tires on the vehicle (see the
SECTION 3E
WHEELS AND TIRES
The Wheel bolt and nut fasteners are an important
NOTICE:
INDEX
tires except in
WHEELS AND TIRES
Tire Inflation Pressure............................................... 3E-3
Correcting Irregular Tire Wear................................. 3E-4
Wheel Installation....................................................... 3E-7
Tire Mounting and Demounting............................... 3E-8
Tire Repair................................................................... 3E-9
Wheel Nut Torques.................................................... 3E-9
Certification Label Fig. 3E-3). Use of any other size or type
tire may affect load carrying capacity, ride, handling,
speedometer/odometer calibration,
clearance, and tire clearance to the body and chassis. If
replacing only a single tire, it should be paired on the same
axle with the least worn tire of the others.
All tires on four-wheel drive vehicles must be of equal
size (but not necessarily ply rating) and of same tread
configuration.
Replace tires when:
1. Tires are worn to a point where 2/32 inch (1.6
millimetres) or less tread remains, or the cord or fabric is
exposed. To help detect this, tires have built-in tread wear
indicators (Fig. 3E-2) that appear between the tread grooves
when the tread depth is 2/32 inch (1.6mm) or less. When
the indicators appear in two or more adjacent grooves at
three spots around the tire, the tire should be replaced.
2. Tire thread or sidewall is cracked, but, or snagged
deep enough to expose the cord or fabric.
3. Tire has a bump, bulge, or split.
4. Tire sustains a puncture, cut, or other injury that
can't be correctly repaired because of the size or location
of the injury.
METRIC TIRES
Metric tires are available in two load ranges, Standard
load and Extra load. Figure 3E-1 shows the meaning of the
metric tire format. Most metric tire sizes do not have exact
corresponding alpha tire sizes. For example, a P205/75R15
is not exactly equal in size and load carrying capacity to an
FR78-15. For this reason, replacement tires should be of the
same size, load range, and construction as those originally
on the car. If metric tires must be replaced with other sizes,
3E-1
vehicle ground
L IG H T T R U C K SER V IC E M AN UAL