Section 04-04: Wheels and Tires | 1996 F-150, F-250, F-350, F-Super Duty Chassis Cab, F-Super Duty Motorhome Chassis and Bronco Workshop Manual |
There are two types of wheel and tire balance: static and dynamic.
Static Balance
Static balance is the equal distribution of weight around the wheel. Wheels that are statically unbalanced cause a bouncing action called wheel tramp. This condition will eventually cause uneven tire wear.
Dynamic Balance
A dynamic balance is the equal distribution of weight on each side of the centerline, so that when the tire spins there is no tendency for the assembly to move from side to side. Unbalanced wheels may cause wheel shimmy.
Clean deposits of mud, etc., from the inside of the rim. Remove stones from the tread. Inspect tire for any damage. Balance according to the equipment manufacturer's instructions.
Balance Weights
Aluminum wheels have thicker rim flanges and require specially designed balance weights. Wheel weights for aluminum wheels are coated to prevent corrosion and should be installed with a plastic mallet.
Off Vehicle
When balancing wheels off the vehicle, use a balancer that pilots the wheel by its center hole.
If the wheel tramp and vehicle vibration are not corrected by the off-vehicle balance, an on-vehicle balance may be needed.
NOTE: Tire and wheel rebalancing should not be required when rotating tires.
NOTE: The balance equipment should have been calibrated by factory-approved technicians within the last 90 days.
Loosen lug nuts (1012) of wheel(s) to be balanced. Raise front or rear of vehicle as required. Refer to Section 00-02.
Remove wheel to be balanced. Remove center cap and mount wheel to balance machine. Lock hub adapter into spindle.
Inspect equipment mounting surfaces, cones, cone springs, wing nuts and mounting cups. They must be clean and without damage.
Remove tire labels, stones, dirt, and any other foreign material from the tire/wheel assembly. Make sure the wheel mounting face and pilot hole are clean and free from foreign material.
Mount the tire/wheel assembly on the machine using a back-mounted cone. Do not mount cone on front side of wheel.
Operate the machine in the DYNAMIC mode only.
Do not remove factory balance weights from the wheel before checking the balance status.
Spin the tire and wheel assembly on the machine in accordance with the balance equipment manufacturer's instructions.
Any tire and wheel assembly that shows a machine reading of 14g (0.50 oz.) or less in the DYNAMIC mode is considered within factory specification when checked on field accurate balance equipment.
If dynamic correction is required, remove and discard the factory balance weights. Re-spin the tire and wheel assembly and add new correction weights in accordance with balance equipment manufacturer's instructions. Never add more than 85g (3 oz.) to either rim flange. Always recheck balance after weight is added.
Remove the tire and wheel assembly from the machine and mount onto the vehicle. Install the center cap.
Position the wheel on the front disc brake hub and rotor (1102) or rear hub (1109).
Install the lug nuts following the appropriate wheel replacement procedure in the Removal and Installation portion of this section. Make sure the cone ends of the lug nuts face inward.
With the lug nuts loosely installed, turn the wheel until one lug nut is at the top of the bolt circle. Tighten the lug nut until snug. In a criss-cross type pattern, tighten the remaining lug nuts until snug to minimize runout.
Lower vehicle.
Evenly tighten the lug nuts in the torque sequence provided, and to the correct torque measurements, in the appropriate wheel replacement procedure in the Removal and Installation portion of this section.
On Vehicle
CAUTION: The suspension should not be allowed to hang free. When the constant velocity joint is run at a very high angle, axle vibrations can occur as well as damage to seals and joints.
The front suspension lower arm (3078) should be supported as far outboard as possible.
If the above method cannot be used, tires should be balanced on a Rotunda Deluxe Wheel Balancer 010-00885 or equivalent.