Chevrolet 1977 light duty truck Service Manual page 332

7. Be sure to re-install the tire inflation valve
caps, if so equipped, to prevent dirt and m ois­
ture from entering the valve core which could
cause air leakage.
* Passenger car tires have 15 inch or smaller
w heel size and have no " LT" designation
m olded in sidewall. Light truck type tires have
" LT" m olded in the sidew all and/or are larger
than 15 inch in w heel size.
Load Range
A
B
C
D
E
Servicing o f tires mounted on
C A U T IO N :
multi-piece rims requires proper tools, safety
equipment and specialized training.
injuries can result from improper servicing
techniques. It is recommended that tires on
multi-piece rims be serviced only by competent
personnel with proper
competent truck tire repair shops.
C O R R E C T IN G IRREGULAR TIRE WEAR
Heel and Toe W ear
This is a saw-toothed effect where one end o f each
tread block is worn more th a n the other. The end that
wears is the one that first grips the road w hen the brakes
are applied.
Heel and toe w ear is less noticeable on rear tires
than on front tires, because the propelling action o f the
rear wheels creates a force which tends to wear the
opposite end of the tread
propelling an d braking, m ake for more even wear o f the
rear tires, w hereas only the braking forces act on the
front wheels, and the saw-tooth effect is more noticeable.
Replaces Ply Rating
2
4
6
8
10
SERVICE OPERATIONS
Severe
equipment or by
blocks. The two forces,
W H E E L C O D E A N D L IM IT S
SIZE OF
CODE WHEEL
15 x 6JJ
DT
XH 15 x 6JJ
XU 15 x 6JJ
FT
15 x 6JJ
A X 15 x 6JJ
X T 15 x 672JJ
BC 15 x 7JJ
CR 15 x 7JJ
AH 15 x 8JJ
BM
15 x 8JJ
BS 15 x 8JJ
CS
15 x 8JJ
DS 15 x 8JJ
BR 16 x 5K
X L
16 x 5 K
YW
16 x 6KS
AM
16 x 6 ' / 2LS
BU
16.5 x 6
DK
16.5 x 6
DW
16.5 x 6
FJ 16.5 x 6
FK
16.5 x 6.75
DJ
16.5 x 6.75
BH 16.5 x 8.25
CM
17.5 x 5.25
FB 19.5 x 6
UH
19.5 x 6
FA
19.5 x 6.75
A certain am ount of heel and toe wear is normal.
Excessive wear is usually due to high speed driving and
excessive use of brakes. The best remedy, in addition to
cautioning the owner on his driving habits,
interchange tires regularly.
Side W ear
This may be caused by incorrect wheel camber,
underinflation, high cambered
corners at too high a rate o f speed. The first two causes
are the most common. C am ber w ear can be radily
identified because it occurs only on one side o f the
treads, whereas underinflation causes wear on both sides.
C am ber wear requires correction o f the cam ber first and
then interchanging tires.
correction for high cam bered roads. Cornering w ear is
discussed further on.
M isalignm ent W ear
This is w ear due to excessive toe-in or toe-out. In
either case, tires will revolve with a side motion and
scrape the tread ru bb er off. If misalignment is severe, the
ru bber will be scraped off o f both tires; if slight, only
WHE EL LIM ITS
M AX. M A X .
LOA D (LBS) PRESS (PSD
1670 55
1670 55
1670 55
1910 70
2040 70
1690 40
1670 40
1670 40
1910 40
1910 40
1760 40
2030 40
2030 40
1800 55
1800 55
2440 75
2780 85
1730 55
2350 70
2680 85
2680 85
2680 85
3170 85
2750 70
2155 70
2540
80
2780 95
2850 90
is to
roads or by taking
There is, o f course, no