OPERATOR'S MANUAL

Tires and Wheels Preventive Maintenance
– 208 – Y53-6027
Medium Duty (R05/09)
Wheel Mounting and Fastening
After the vehicle travels about 50 to 100 miles (80 to 160 km),
wheel mountings “seat in” and will lose some initial torque.
Check hub/wheel mountings after this initial period and
retighten.
Wheel Cap Nut Torque
At the first scheduled lube interval, have all wheel cap nuts
torqued to their specified value. See
Table 7, “Wheel Cap
Nut Torque,” Page 210 After that, check wheel cap nuts at
least once a week. Contact an Authorized Service Center for
information on the proper installation procedure for the
wheels on your truck. This is a job you may not be able to do
yourself if you do not have the right equipment.
WARNING! Never use oil or grease on studs or
nuts; improper torque readings will result, which
could cause improper wheel clamping and could
lead to a wheel failure resulting in an accident
causing death or personal injury.
Wheel Bearing Adjustment
For safe, reliable operation and adequate service life, your
wheel bearings must be checked and adjusted properly at
the recommended intervals. See Table 2, “Maintenance
Schedule,” Page 113, and Table 2, “Maintenance Sched-
ule,” Page 157. The person best equipped to do this is your
Authorized Service Center's mechanic.
Table 6 Effect of Load Pressure on Tire Life
Vehicle Load Normal 20% Over 40% Over 60% Over 80% Over 100% Over
Tire Pressure Normal 20% Low 30% Low 35% Low 45% Low 55% Low
Expected Total Tire
Mileage
Normal 70% 50% 40% 30% 25%