Tire and Wheel Assembly Balancing - Off Vehicle 19.5 Wheels

Caution: Failure to adhere to the following precautions before tire balancing can result in personal injury or damage to components:

Tire and wheel balancers can drift out of calibration over time, or can become inaccurate as a result of heavy use. There will likely not be any visual evidence that a calibration problem exists. If a balancer is not calibrated within specifications, and a tire and wheel assembly is balanced on that machine, the assembly may actually be imbalanced.

Tire and wheel assembly balancer calibration should be checked approximately every two weeks if the machine is used frequently, and/or whenever the balance readings are questionable.

Check the calibration of the tire and wheel assembly balancer according to the manufacturer's recommendations, or use the following procedure.

Important: If the balancer fails any of these steps, the balancer should be calibrated according to the manufacturer's instructions. If the balancer cannot be calibrated, contact the manufacturer for assistance.

1. Spin the balancer without a wheel or any of the adapters on the shaft.
2. Inspect the balancer readings.

Specification
Zero within 7 g (¼ oz)

3. If the balancer is within the specification range, balance a tire and wheel assembly (that is within radial and lateral runout tolerances) to ZERO, using the same balancer.
4. After the tire and wheel assembly has been balanced, add an 85 g (3 oz) test weight to the wheel at any location.
5. Spin the tire and wheel assembly again. Note the readings.

•	In the static and dynamic modes, the balancer should call for 85 g (3 oz) of weight, 180 degrees opposite the test weight.

•	In the dynamic mode, the weight should be called for on the flange of the wheel opposite the test weight.

6. With the assembly imbalanced to 85 g (3 oz), cycle the balancer 5 times.
7. Inspect the balancer readings:

Specification
Maximum variation: 7 g (¼ oz)

8. Index the tire and wheel assembly on the balancer shaft, 90 degrees from the previous location.
9. Cycle the balancer with the assembly at the new location.
10. Inspect the balancer readings:

Specification
Maximum variation: 7 g (¼ oz)

11. Repeat steps 8 through 10 until the tire and wheel assembly has been cycled and checked at each of the four locations on the balancer shaft.

Important: Tire and wheel assemblies which exhibit excessive runout can produce vibrations even if the assemblies are balanced.

There are two types of tire and wheel balance:

Static Balance

Static balance is the equal distribution of weight around the wheel circumference. The wheel balance weights (2) are positioned on the wheel in order to offset the effects of a heavy spot (3). Wheels that have static imbalance can produce a bouncing action called tramp.

Dynamic Balance

Dynamic balance is the equal distribution of weight on each side of the tire and wheel assembly centerline. The wheel balance weights (2) are positioned on the wheel in order to offset the effects of a heavy spot (3). Wheels that have dynamic imbalance have a tendency to move from side to side and can cause an action called shimmy.

Most off-vehicle balancers are capable of checking both types of balance simultaneously.

As a general rule, most vehicles are more sensitive to static imbalance than to dynamic imbalance, however, vehicles equipped with low profile, wide tread path, high performance tires and wheels are susceptible to small amounts of dynamic imbalance. As little as 14 to 21 g (½ to ¾ oz) imbalance is capable of inducing a vibration in some vehicle models.

Important: When balancing tire and wheel assemblies, use a known good, recently calibrated, off-vehicle, two-plane dynamic balancer set to the finest balance mode available.

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
2. Mark the location of the wheels to the wheel studs and mark the specific vehicle position on each tire and wheel (LF, LR, RF, RR).
3. Remove the tire and wheel assemblies one at a time and mount on a spin-type wheel balancer. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
4. Carefully follow the wheel balancer manufacturer's instructions for proper mounting techniques to be used on different types of wheels.

Regard aftermarket wheels, especially those incorporating universal lug patterns, as potential sources of runout and mounting concerns.

5. Be sure to use the correct type of wheel balance weights for the type of wheel rim being balanced. Refer to Wheel Weight Usage, following.
6. Balance all four tire and wheel assemblies as close to zero as possible.
7. Using the matchmarks made prior to removal, install the tire and wheel assemblies to the vehicle. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
8. Lower the vehicle.

Tire and wheel assemblies can be balanced using either the static or dynamic method.

Wheel Weight Placement - Static Balancing

When static balancing, locate the wheel balance weights on the inboard flange (2) if only 28 g (1 oz) or less is called for; if more than 28 g (1 oz) is called for, split the weights as equally as possible between the inboard (2) and outboard (1) flanges.

Wheel Weight Placement - Dynamic Balancing

When dynamic balancing, locate the clip-on wheel balance weights on the inboard (2) and outboard (1) rim flanges at the positions specified by the wheel balancer.

Clip-on Weights

The type of wheel balance weight for use on steel wheels (only) is type P (3).