262 Auto Suspension and Steering
stationary vehicle. On most vehicles, the hub is also the
mounting surface for the brake drum or rotor. On non-
driving axles, the hub often contains the bearing races.
Note the relationship between the hub, the tapered roller
bearings and the spindle in Figure 12-30. This design is
often used on front or rear non-driving wheels.
The front hubs used on many front-wheel drive
vehicles are pressed onto the axle. Splines on the hub and
the axle allow the axle to drive the hub. The hub may be
pressed into the bearings.
When solid axles are used, such as on the rear of rear-
wheel drive vehicles, the axle and drum are connected
through the use of an axle flange, Figure 12-31. The axle
flange is forged as part of the axle, or it is welded on later.
The flange forms a mounting surface for the wheel
assembly.
Wheel Rims
Wheel rims are the connection between the hub and
the tire. The tire is installed on the rim, and the
rim is bolted to the hub.
Rim Construction
In many cases, rims are made of stamped steel,
Figure 12-32. Parts of the rim are stamped into shape and
then welded into a final form. The center section contains
Free
I.D.
Shaft
dia.
Outside
face
I.D.
Bore
dia.
Seal
O.D.
Inside
face
I.D.
Width
Outside
face
Inside face
Tension spring
Seal lip
Axial
clearance
Figure 12-28. A cross-sectional view of one type of oil seal.
(General Motors)
Axle housing
Oil
seal
Straight
roller
bearing
Axle shaft
Brake
backing plate
Brake drum
Figure 12-29. An oil seal pressed into the axle housing bore.
Note that this axle uses straight roller bearings.
(General Motors)
Hub
Tapered roller
bearing
Spindle
Seal
Tapered roller
bearing
Figure 12-30. This cross section shows the relationship
between the hub, the tapered roller bearings, and the spindle.
(Hyundai)