Chevrolet 30 Series 1967 Service Manual page 476

WHEELS AND TIRES 10-2
TRUCK TYPE
Tire Size
Tubeless
Tube- Type
7.00-14
7.00-14
6.50-16
7-17.5 7.00-15
7.00-16
7.50-16
7o5 0-16
7-22,5
7.00-20
#8-16.5
8-17.5
7.00-17
8-17.5 7.00-17
8-19.5
7.00-18
8-19.5 7.50-17
8-19.5 7.50-17
7.50-20
7.50-20
8.25-20
8.25-20
9.00-20
9.00-20
10.00-20
#NOTE: 25 PSI - 1230 Load, 30 PSI - 1360 Load
Wheel Nut Torques
On all vehicles equipped with disc or cast spoke
wheels, it will be necessary to retorque the wheel nuts at
firs t 1000 miles and every 6000 miles thereafter. See
Specifications for correct nut torques.
Correcting Irregular Tire Wear
Heel and Toe W ear--This is a saw-toothed effect where
one end of each tread block is worn more than the other.
The end that wears is the one that first grips the road
when the brakes are applied.
Heel and toe wear is less noticeable on rear tires than
on front tires, because the propelling action of the rear
wheels creates a force which tends to wear the opposite
end of the tread blocks. The two forces, propelling and
braking, make for more even wear of the rear tires,
whereas only the braking forces act on the front wheels,
and the saw-tooth effect is more noticeable.
A certain amount of heel and toe wear is normal.
cessive wear is usually due to high speed driving and ex­
cessive use of brakes. The best remedy, in addition to
cautioning the owner on his driving habits, is to inter­
change tires regularly.
Side Wear—This may be caused by incorrect wheel
camber, underinflation, high cambered roads or by taking
corners at too high a rate of speed.
The first two causes are the most common. Camber
wear can be readily identified because it occurs only on
one side of the treads, whereas underinflation causes
wear on both sides. Camber wear requires correction of
the camber first and then interchanging tires.
There is, of course, no correction for high cambered
roads. Cornering wear is discussed further on.
Ply
Rating 35 40 45
6
990 1070 1145
8 990 1070 1145
6
1225 1320 1420
6
1310 1420 1520
6 1365 1475 1580
6 1565
1690 1815
8
1565 1690 1815
6 1640 1760
8
1640 1760
6 1490 1610 1730
6
1620 1735
6
1620 1740
8
1620 1740
6
1830 1960
8
1690 1810
8
1830 1960
10 1830
1960
8 2060
2210
10 2060
2210
10 2400
2570
12
2400 2570
10
3040
12
3040
12
SERVICE OPERATIONS
Ex­
Loads and Inflation Pressures (Lb./Sq. In.)
50 55 60
1220 1290 1365
1930 2040 2140
1870
1870 1980 2080
1850 1960 2060
2090
1920 2040 2140
2090 2220 2330
2090 2220 2330
2350 2490 2620
2350 2490 2620
2730 2890 3040
2730 2890
3040
3240 3440
3620
3240
3440 3620
3600 3820 4020
Misalignment W ear--This is wear due to excessive
toe-in or toe-out. In either case, tires will revolve with
a side motion and scrape the tread rubber off. If mis­
alignment is severe, the rubber will be scraped off of
both tires; if slight, only one will be affected.
The scraping action against the face of the tire causes
a small feather edge of rubber to appear on one side of
the tread and this feather edge is certain indication of
misalignment. The remedy is readjusting toe-in, or re­
checking the entire front end alignment if necessary.
Uneven Wear--Uneven or spotty wear is due to such
irregularities as unequal caster or camber, bent front
suspension parts, out-of-balance wheels, brake drums
out of round, brakes out of adjustment or other mechan­
ical conditions. The remedy in each case consists of
locating the mechanical defect and correcting it.
Cornering Wear--When a truck makes an extremely
fast turn, the weight is shifted from an even loading on
all wheels to an abnormal load on the tires on the outside
of the curve and a very light load on the inside tires, due
to centrifugal force.
unfavorable results.
F irst, the rear tire on the inside of the curve may be
relieved of so much load that it is no longer geared to
the road and it slips, grinding off the tread on the inside
half of the tire at the excessive rate. This type of tire
shows much the same appearance of tread wear as tire
wear caused by negative camber.
Second, the transfer of weight may also overload the
outside tires so much that they are laterally distorted
resulting in excessive wear on the outside half of the tire,
producing a type of wear like that caused by excessive
positive camber.
65 70 75 80
2180
2440
2440
2650
2740
2740
2860 2980 3090
3180 3330
3180 3330 3460 3600
3790 3960
3790 3960 4120 4280
4220 4410
4580
This unequal loading may have two
CHEVROLET TRUCK SERVICE MANUAL
85
3730
4480