Chevrolet 1977 light duty truck Service Manual page 328

W HEEL
W HEEL
HUB
FRONT
FRONT & REAR
W/SINGLE REAR W /D U A L REAR
Fig. 1--Wheel A ttachm ents
W HEEL R E P LA C E M E N T C O N S ID E R A T IO N S
Wheels must be replaced if bent, heavily rusted,
leak air, or if lug nuts continually loosen. Do not
straighten bent wheels or use inner tubes in leaking
wheels used with tubeless tires. The wheels originally
equipped on the vehicle will provide optim um life up to
the m axim um load and inflation pressures as shown in
the Wheel Code and Limits Chart. M axim um loads,
m axim u m inflation pressures, wheel identification codes,
and wheel sizes are stam ped on each wheel.
W h e n rep la c in g wheels
replacem ent wheels should
capacity, inflation pressure capacity, diameter, width,
offset, and m o unting configurations to those originally
installed on the vehicle.
A wheel of im pro per size or type may adversely
affect load carrying capacity, wheel and bearing life,
brake cooling, sp e e d o m e te r/o d o m eter calibration, vehi­
cle ground clearance, and tire clearance to the body and
chassis. Replacem ent with " u s e d " wheels which may
have been subjected to harsh operating conditions or
very high mileage is not recommended. These wheels
m ay fail prem aturely without any prior visual indication.
N O T E : The use of wheels a n d / o r tires with higher
load carrying capacity than originally equipped on
the vehicle does not
G A W R 's or the G V W R o f the vehicle. Wheels
having diameters ran ging from 16 inch through
19.5 inch diam eter tha t have also been certified for
radial tire application up to the maxim um load and
m axim um tire pressure wheel limits shown in the
W heel Code and Limits Chart have the word
" r a d ia l" stamped on the rim. Wheels in the 16 inch
through 19.5 inch d ia m e te r range without the
" r a d ia l" identification stam p are not to be used
with radial tires.
OUTER
DUAL REAR
MAINTENANCE
for any reason, the
be equivalent in load
necessarily increase the
Fig. 2 -T ire Rotation
WHEEL N U T TORQUES
On a new vehicle or after the wheel has been
changed, the wheel nut torque must be checked at 100,
1,000 and 6,000 miles and every 6,000 miles thereafter.
TIR E IN S P E C T IO N AND R O T A TIO N
Front and rear tires perform different jobs and can
wear differently depending on the type o f roads driven,
individual driving habits, etc. To obtain m axim um tire
life, tires should be inspected and rotated regularly.
Bias-belted tires should be rotated every 7,500 miles
(passenger car type tires); 6,000 miles (truck type tires).
Radial tires should be rotated at the first 7,500 miles and
then at least every 15,000 miles th ereafter (passenger car
type tires); first 6,000 miles then every 12,000 miles
(truck type tires). For the longest tire life, any time
irregular w ear is noticed, the tires should be inspected
and rotated and the cause o f the uneven w ear corrected.
Be certain to check wheel nut tightness and to adjust the
tire pressures, front and rear, after rotation to agree with
those recomm ended in the tire inflation charts.
The outer tire on a dual wheel will skid or drag on a
turn because o f the difference in the turning radii o f the
inner and outer tires. This results in faster w ear o f the
outer tire. In general, the tire with the largest diam eter
or least w ear whould be at the outside o f each dual
wheel. In addition, when trucks are operated continu­
ously on high crown roads an increase in air pressure of
from 5 to 10 PSI in the outside tire o f each dual
produces m aximum tire life.
IN F LA TIO N PRESSURE
The m axim um cold inflation
factory installed tires are listed on the VIN plate. Tires
must be inflated to these pressures when the G V W R or
an axle G A W R is reached. Im proper tire inflation
pressures for the load
adversely affect tire life and vehicle performance.
pressures for the
the vehicle is carrying can