Medium Duty Operator's Manual - Peterbilt Motors Company

Preventive Maintenance
Tire Replacement
Front: replace front tires when less than 4/32 in. of tread
depth remains. Check depth at three places equally spaced
around the tire.
Drive Axles or Trailers: replace tires on drive axles when
less than 2/32 in. of tread depth remains in any major groove.
Check depth at three places equally spaced around the tire.
WARNING! Do not install regrooved or reinforcement-repaired
tires on steering axles. They
could fail unexpectedly and cause you to lose
control of your vehicle resulting in an injury
accident.
WARNING! Do not replace original equipment
tires with load ratings less than the original
tires. Doing so could lead to unintentional overloading
of the tire, which could cause a failure
resulting in loss of vehicle control and an injury
accident.
Tires and Wheels
NOTE: To prolong the tires' life and make them
safer, have their radial and lateral run-out checked at
your Peterbilt Dealer. And of course have the tires
balanced any time you change a tire.
Matching Tires
Be sure to buy matched tires for your vehicle, especially on
the rear axles. Mismatched tires can cause stress between
axles and cause the temperature of the axle lubricant to get
too hot. Matched tires will help the driveline last longer and
will give you better tire mileage.
WARNING! Do not mismatch tires, it can be dangerous.
Never mix tires of different design such
as steel belted radials and bias ply tires, etc.
Mixing tire types and sizes will adversely affect
the road-holding ability of both types of tires and
can lead to loss of vehicle control and serious
personal injury.
Make sure, too, that you use the right size tires on each
wheel. Some trucks require different sizes on front and rear
wheels. For safety, always use the recommended size and
type of tires.
Medium Duty (R05/09) Y53-6008A – 209 –