Chevrolet 1980 Light Duty Truck Service Manual page 311

RADIAL TIRES
Recommended truck tire mounting and inflation
procedures are especially important with radial truck tires.
Failure to follow these recommendations can cause bead
deformation in both tube type and tubeless tires due to
incorrect bead seating. Bead deformation may lead to
chafing, lower sidewall and bead area cracking, demounting
difficulties, eccentric wear, ride vibration and non-
retreadable casing.
M ounting
To insure correct mounting and bead seating and to
prevent bead deformation, the following steps must be
taken:
A. Tube Type Tires
1. Only use rims approved for radial tire usage by rim
manufacturer. Thoroughly clean rim parts, removing all
rust and other foreign material. Make sure rim parts match
and are not sprung or broken.
2. Thoroughly lubricate tire beads, portion of tube
between beads, and flaps with an approved rubber lubricant.
Radial tubes are identifiable by the letter "R" in the size
designation. Example 100R20. Also, to further identify the
radial tube, a red band on the valve stem has been required
since March, 1975. Radial flaps are also identified by the
letter "R". Example - 20R8.
NOTICE: Do not use silicone base lubricants - this
could cause the tire to slip on the wheel.
3. Double inflate. Inflate to operating pressure, deflate
completely and reinflate to operating pressure. This allows
tube, flap and tire to fit together properly.
4. Check bead seating. Visually check slot and side
ring gap (on two piece rim) to make sure bead is seated. The
flange and one of the three lower sidewall rim line rings
while the tire is laying flat (measurements should be taken
each 90° around the circumference of the rim flange). If
spacing is uneven around bead from side to side, repeat Step
1 through 3, and recheck.
B. Tubeless Tires.
1. Only use rims approved for radial tire usage by rim
manufacturer. Thoroughly clean rim, removing all rust and
other foreign material.
2. Thoroughly lubricate tire beads and rim bead seats
with an approved rubber lubricant.
Do not use silicone base lubricants - this
NOTICE:
could cause the tire to slip on the wheel.
W HEELS AND TIRES
Series Description
K 7/16" Bolts (6)
C10,P10,G10,G20
1/2" Bolts (5)
C20, P20
C30, P30 and 9 /1 6 " Bolts (8)
K20, G30
Single Wheels
9 /1 6 " Bolts (8)
CKPG30 Heavy Duty
Dual Wheels Wheels
5 /8" Bolts (10)
Fig. 3E-1 2-Wheel Nut Torque
3. Inflation. Inflate tire to operating pressure. Due to
the construction of radial truck tires, particularly in the
lower sidewall and bead area, it may be difficult to get the
tire to take air. An inflation aid may be necessary to help
seat the bead of tubeless radial tires. Two types of inflation
aids are commercially available, (1) metal rings which use
compressed air to seat beads, and (2) rubber rings which seal
between the tirebead and rim bead seat allowing the bead
to move out and seat. Lubrication is mandatory with both
items.
4. Check bead seating. This check is made by
measuring the space between the rim flange and one of the
three lower sidewall rim line rings while the tire is laying
flat (measurements should be taken each 90° around the
circumference of the rim flange. If spacing is uneven around
the bead from side to side, repeat Steps 1 through 3, aqd
recheck.
It's important that this procedure be followed to insure
proper bead seating in order to prevent bead deformation.
Radial tires, as well as the bias tires, must be mounted
and inflated in accordance with safety precautions noted in
RMA Radial and Bias Truck Tire Service Manuals.
TIRE REPAIR
There are many different materials and techniques on
the market to repair tires. As not all of these work on all
types of tires, tire manufacturers have published detailed
instructions on how and when to repair tires. These
instructions can be obtained from the tire manufacturer.
3E-9
Torque
70-90 Ft. Lbs.
75-100 Ft. Lbs.
90-120 Ft. Lbs.
110-140 Ft. Lbs.
130-180 Ft. Lbs.
LIG H T T R U C K SER V IC E M ANUAL