Wheels and Tires: Description and Operation

WARNING: Do not mix different types of tires, such as radial, bias, or bias-belted, on the same vehicle except in emergencies (temporary spare usage). Vehicle handling can be seriously affected and can result in loss of control.

Factory-installed tires and wheels are designed to operate satisfactorily with loads up to and including full-rated load capacity when inflated to recommended inflation pressures.
Correct tire pressure and driving techniques have an important influence on tire life. Heavy cornering, excessively rapid acceleration and unnecessary sharp braking increase tire wear.
Replacement tires should follow the recommended:
- tire sizes.
- speed rating.
- load range.
- radial construction type.
Use of any other tire size or type may seriously affect:
- ride.
- handling.
- speedometer/odometer calibration.
- vehicle ground clearance.
- tire clearance between the body and chassis.
- wheel bearing life.
- brake cooling.
New wheels need to be installed when:
- bent.
- dented.
- heavily rusted.
- leaking.
- they have elongated wheel hub bolt holes.
- they have excessive lateral or radial runout.
The Expedition uses a two-piece wheel nut, containing the nut and a washer.
Wheel and tire assemblies are attached by five noncentering wheel nuts.
When balancing wheels and tires, use T-type balancing weights.
The spare tire is mounted under the frame. The valve stem should be on the top side of the tire to reduce the possibility of accidental valve stem air leakage.
To equalize tire wear, rotate the tires periodically.