Road Test: Notes

A tire vibration diagnostic procedure always begins with a road test. The road test and customer interview (if available) will provide much of the information needed to find the source of a vibration.

During the road test, drive the vehicle on a road that is smooth and free of undulations. If vibration is apparent, note and record the following:

• The speed at which the vibration occurs.
• What type of vibration occurs in each speed range - mechanical or audible.
• How the vibration is affected by changes in vehicle speed, engine speed, and engine torque.
• Type of vibration sensitivity - torque sensitive, vehicle speed sensitive, or engine speed sensitive.

Use the following explanation of terms to help isolate the source of the vibration.