Tires and Rims
14
PCMS Operations, Safety & Maintenance V3.0
Ver-Mac 2018
5
Tires and Rims
Each trailer has rims installed that are designed for stability requirements. Trailer stability is
based on trailer width, tire pressure, and load capacity.
Size changes may result in an unsafe condition regarding stability.
The size of the trailer tires and also the rims fitted on the PCMS unit varies according to the
gross
axle
weight
rating
(GAWR):
GAWR 3500 lb = ST205/75D15 5 hole rim and 6ply trailer tires for the Class II trailers
GAWR 5000lb = ST225/75R15 6 hole rim and 6ply trailer tires for the Class III trailers
Tire Safety Checklist
Check that tires are inflated to specified pressure (32 psi), especially
before towing
Make sure the tire valves have valve caps and are not
touching/rubbing the rim or wheel
Inspect tires for signs of wear, cracks or impact damage
Remove any foreign objects wedged in tread (bits of glass, etc.)
Tighten wheel bolts at 90-120 ft-lb (122-167 N.m.)
5.1
Trailer Tire Wear Diagnostic Chart
CAUTION
Variations in tire pressure can adversely affect handling and
stability of unit trailer
.
Wear Pattern
Cause
Action
Center Wear
Over-inflated tire
Adjust pressure
Edge Wear
Under-inflated tire
Adjust pressure
Side Wear
Loss of camber or
overloading
Make sure load does not
exceed axle rating.
Realign load or axle
Cupping
Out of balance
Check bearing
adjustment and balance
tires