For 1990-2009 cars

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

• | Clean away any dirt or deposits from the inside of the wheels.

• | Remove any stones from the tread.

• | Wear eye protection.

• | Use coated weights on aluminum wheels.

Important: On-vehicle balancing is not recommended on the Catera due to the silicone injected front control arm bushings. Only off-vehicle balancing is recommended.

Tire and wheel balancers can drift out of calibration without warning, or can become inaccurate as a result of abuse. The balancer calibration should be inspected according to the manufacturer's requirements.

### Tire Balancer Calibration Test

Important: Calibrate the tire balancer according to the manufacturer's recommendations, or use the following procedure.

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

Specification
0-7 g (0.00-0.25 oz)

3. Balance a tire and wheel assembly that is within radial and lateral tolerances to ZERO.
4. Add an 85 g (3 oz) test weight to the wheel at any location.
5. Spin the tire and wheel assembly again. Observe 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 only, the weight should be called for on the flange of the wheel opposite the last weight.

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

Specification
Variation: 7 g (0.25 oz) or less

8. Index the tire and wheel assembly at 4 separate locations on the balancer shaft, 90 degrees apart.
9. Cycle the balancer with the assembly at each location.
10. Take the balancer readings:

Specification
Variation: 7 g (0.25 oz) or less

### Tire Balancing Guidelines

Static and dynamic balance are the two kinds of tire/wheel balance:

• | Static balance, also called single plane balance, affects the distribution of weights around the wheel circumference.

• | Dynamic balance, or two-plane balance, affects the distribution of weight on each side of the tire/wheel centerline.

Most off-vehicle balancers can check both types of balance simultaneously.

As a general rule, most vehicles are more sensitive to static imbalance than to dynamic imbalance. As little as 14-21 g (0.50-0.75 oz) may induce a vibration in some vehicles. Vibration induced by static imbalance will cause a vertical, or bouncing, motion of the tire.

Dynamic imbalance results in a side-to-side motion of the tire, or shimmy.

• | Balance all 4 tires as close to ZERO as possible.

• | Carefully follow the wheel balancer manufacturer's instructions for proper mounting techniques for different types of wheels.

• | Aftermarket wheels, especially those incorporating universal lug patterns, are potential sources of runout and mounting problems.

• | Use the correct coated weights on aluminum wheels.

• | Retest the tire and wheel assemblies for excessive runout after correction and installation.

• | Evaluate the vehicle at the complaint speed and note if the vibration has been corrected.

• | If the vibration is still present, or is reduced but still unacceptable, consider these possibilities:

- | On-vehicle imbalance

- | Radial or lateral force variation

### Correcting On-Vehicle Imbalance

On-vehicle imbalance may result from components other than the tire and wheel assemblies having imbalance. An on-vehicle high-speed balance or replacement of suspected components may be necessary in order to correct the condition.

Rotors do not have a set tolerance. However, rotors with more than 0.75 ounce imbalance have the potential to cause vibration. The rotors can be inspected for imbalance using either the on-vehicle or the off-vehicle method as described below:

### Checking Rotor Imbalance (Off-Vehicle)

1. Measure the diameter and the width of the rotor.
2. Mount the rotor on a balancer in the same manner as a wheel.

Important: The rotors can only be inspected for static imbalance. Ignore the dynamic imbalance reading.

3. Inspect for static imbalance and obvious deficiencies.