Wheels And Tires; Tire Construction; Identifying Tire Types - Jeep 1979 CJ-5 Technical & Service Manual

2H"1
S E C T I O N I N D E X
Abnormal Tin Wear
leneral
Radial Wide Tread, and Snow Tin Applications
Specifications
Tire Construction
Tire Inflation Pressure and Capacity
Tire Maintenance and Condition
Tire Repair
2H-3
2H-1
2H-5
2H-11
2H-1
2H-2
2H-4
2H-4
Page
Tire Rotation 2H-5
Tire Roughness 2H-7
Tire Size and Load Rating 2H-2
Vibration 2H-9
Wheels 2H-5
Wheel Balancing 2H-5
Wheel Bearing Adjustment 2H-5
Maintenance and Condition 2H-5
CE1ERAL
Jeep vehicles are equipped with American and Metric
size, tubeless-type, pneumatic tires available in load
ranges SL, B, C, and D. Standard equipment tires are of
bias-ply or bias-belted construction. Radial-ply tires are
available as an option on most models.
Standard equipment wheels are safety rim, drop cen-
ter-types constructed entirely of steel. Optional wheels,
which are available on most models, consist of forged
aluminum wheels, wide rim spoke-type sport wheels,
and chrome plated styled steel wheels.
Original equipment wheels and tires are tested and
selected to provide the best all around performance for
normal operation. To obtain optimum wheel/tire per-
formance, tire inflation pressures must be maintained
at recommended levels and wheel/tire condition should
be checked regularly. This is especially important on
vehicles equipped with the Quadra-Trac full-time four
wheel drive transfer case.
TIRE CONSTRUCTION
Three types of tire construction are currently in use.
They are referred to as bias-ply, bias-belted, and radial-
ply construction. The description for each construction-
type is derived from the method used to position the tire
cord plies in relation to the tread centerline.
Bias-Ply Construction
Bias-ply tires are constructed with the body cord plies
extending from bead-to-bead and at an angle to the
tread centerline (fig. 2H-1). Alternate plies overlap one
another at opposing angles.
Bias-Belted Construction
Bias-belted tires are constructed basically the same as
bias-ply tires. However, in addition to the angled body
cord plies, they also have belts that encircle the tire.
These belts are located under the tire tread and extend
from tread shoulder-to-tread shoulder (fig. 2H-1).
Radial-Ply Construction
Radial-ply tires, like bias-belted tires, also have belts
under the tread which encircle the tire and extend from
* tread shoulder-to-tread shoulder. However, these tires
are constructed with the body cord plies at right angles
to the tread centerline. The plies cross the tread center-
line at an angle of approximately 90 degrees (fig. 2H-1).
Because the body cord plies radiate from the tread cen-
terline, this type of construction is designated radial-
piy.
Identifying Tire-Types
Radial tires are identified by the code letter R which
appears in the size description imprinted on the tire
sidewall. Bias-ply and bias-belted tires do not have such
a code letter. For example, P225/75R-15 or HR78-15 for
radial tires as compared to H78-15 for similar size bias-
ply or bias-belted tires.
N O T E : As a result of their unique construction, radial
tires have a highly flexible sidewall. This flexibility is