XL-7 Limited 4WD V6-2.7L (2002)
Wheel unbalance causes most of the highway speed vibration problems. If a vibration remains after dynamic balancing, it can be caused by three
things.
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Tire runout.
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Wheel runout.
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Tire stiffness variation.
Measuring tire and/or wheel free runout will uncover only part of the problem. All three causes, known as loaded radial runout, must be checked by
using a Tire Problem Detector (TPD). If a TPD is not available, the more time consuming method of substituting known good tire and wheel
assemblies on the problem vehicle can be used.