GMC 1982 Light Duty Truck Service Manual page 395

FRONT
r l n p i n
L|J L|J l|
4 WHEEL
ROTATION
•
PREFERRED FOR
RADIAL TIRES
CAUTION: Servicing of tires mounted on multi­
piece rims requires proper tools, safety equipment
and specialized training. Severe injuries can result
from improper servicing
recommended that tires on multi-piece rims be
serviced only by competent personnel with proper
equipment or by competent truck tire repair shops.
TIRE INSPECTION AND ROTATION (Figs. 3E-4,
3E-5)
Front and rear tires perform different jobs and can
wear differently depending on the type of roads driven,
individual driving habits, etc. To obtain maximum tire life,
tires should be inspected at intervals shown in Section OB.
For the longest tire life, any time irregular wear is noticed,
the tires should be inspected and rotated and the cause of the
uneven wear corrected. Be c erta in to check wheel nut
tightness and to adjust the tire pressures, front and rear,
after rotation to agree with those recommended in the tire
inflation charts.
The outer tire on a dual wheel will skid or drag on a
turn because of the difference in the turning radii of the
inner and outer tires. This results in faster wear of the outer
tire. In general, the tire with the largest diameter or least
wear whould be at the outside of each dual wheel. In
addition, when trucks are operated continuously on high
crown roads, an increase in air pressure of from 5 to 10 PSI
in the outside tire of each dual produces maximum tire life.
^FRONT
r
\ A
WHEEL
5
DTATION
R<
* THE OPTIONAL 'X ' ROTATION PATTERN FOR
RADIALS IS ACCEPTABLE WHEN REQUIRED
FOR MORE UNIFORM TIRE WEAR.
Fig. 3E-5--Tire Rotation
SERVICE OPERATIONS
techniques. It is
FRONT
i
r
IXI I/I
1 1
4 »
r o
• OPTIONAL FOR
RADIAL TIRES *
• M A N D A TO R Y FOR
BIAS TIRES
As shown in Fig. 3E-5, the X method of rotation is
allowed with radial tires if necessary. Due to their design,
radial tires tend to wear faster in the shoulder area
particu larly in the front positions. This makes regular
rotation especially necessary.
INFLATION PRESSURE
The maximum cold inflation pressures for the factory
installed tires are listed on the Certification Label. Tires
must be inflated to these pressures when the G V W R or an
axle G A W R is reached. Improper tire inflation pressures for
the load the vehicle is carrying can adversely affect tire life
and vehicle performance.
For improved ride comfort in vehicles rated at 8600
G V W R , it is permissible to use the lower tire pressure values
shown on the label located on the rear edge of the driver's
door provided there is a maximum of 200 lbs. cargo, no slide
in camper, and there are three or less occupants.
Too low an air pressure can result in tire overloading,
abnormal tire wear, adverse vehicle handling, and reduced
fuel economy. T h e tire flexes more and can build up
excessive heat, weakening
susceptibility to damage or failure. Too high an air pressure
can result in abno rm al wear, harsh vehicle ride, and
increased susceptibility to dam a g e from road hazards.
Lower inflation pressures should be used only with reduced
vehicle loads and the rear tire pressure should be equal to or
greater than the front pressure on single wheel application.
A fter determ ining the
WHEELS A N D TIRES
FRONT
rl n
JjDjh)
the tire and increasing
load on each tire
3E-3
by