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.
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.
Specification
Zero within 7 g (¼ oz)
• | 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. |
Specification
Maximum variation: 7 g (¼ oz)
Specification
Maximum variation: 7 g (¼ oz)
Important: Tire and wheel assemblies which exhibit excessive runout can produce vibrations even if the assemblies are balanced.
Therefore, it is strongly recommended that the tire and wheel assembly runout be measured and corrected if necessary before the assemblies are balanced.If the runout of the tire and wheel assemblies has not yet been measured, refer to Tire and Wheel Assembly Runout Measurement - Off Vehicle before proceeding.
There are two types of tire and wheel 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 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.
Regard aftermarket wheels, especially those incorporating universal lug patterns, as potential sources of runout and mounting concerns.
Tire and wheel assemblies can be balanced using either the static or dynamic method.
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.
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.
The type of wheel balance weight for use on steel wheels (only) is type P (3).