Peterbilt 330 - Table 14 Comparing Hub-Piloted and Ball-Seat Wheels

Tires and Wheels Preventive Maintenance
– 180 –
PB1318 3/01 Model 330
Table 14 Comparing Hub-piloted and Ball-seat Wheels
HUB–PILOTED MOUNT
BALL–SEAT MOUNT
Hub, Drum, and Stud Assembly
Hub-piloted mountings use M22 x 1.5 metric threads (about 7/8 in.
diameter). The stud stands out at least 1.94 in. beyond the brake drum.
All studs are right-hand threads. Pilot bosses (machined surfaces) on
the hub, fit tightly to the wheel center bore.
Ball-seat (stud-piloted) mountings use 3/4x16 or 1-1/8x16 threads. The
dual mounting studs provide 1.30 in. –1.44 in. standout. Right-hand
and left-hand threads are required. Inner and outer wheel nuts center
the wheels by seating against wheel ball seats.
Wheels
Hub-piloted wheels have stud holes reamed straight through (no ball
seats). Center bore diameter is 8-21/32 in.
Ball-seat wheels have spherical chamfers machined on each stud hole.
Center bore diameter is 8-23/32 in.
Wheel Nuts
Hub-piloted wheel nuts have a hex body and a flange for clamping
against wheel face. Hex size is 1-5/16 in. (33 mm).
Ball-seat inner and outer wheel nuts mate with spherical chamfers on
wheels. The inner nut has 13/16 in. square end. The outer nut has a
1-1/2 in. hex.
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