Vehicle noises and vibrations occur for many reasons. Some occur during the normal
operation of the vehicle, as in the case of mechanical rotating parts. These include
the engine, transmission, driveline, and tire/wheel assemblies.
Other noises and vibrations may occur due to abnormal conditions, found in tires,
wheels, driveline, and worn parts.
Every vibration consists of three elements.
Source Component (excitation) - a component causing another
object to vibrate.
Transfer Path - the object(s) that transfer the vibration (frequency).
Responding Component - the noticeable component that is vibrating.
The component creating the vibration may be a great distance from the component
actually shaking or making noise.
The problem may be a damper working improperly or missing, which opens the transfer
path to the responding component.
Another possibility is the deterioration of the responding component. Perhaps
it becomes simpler to make it shake, rattle or make noise.
Vibration is divided into two categories:
Forced (vibrates when energy is applied) - An imbalanced
tire vibrates when put in motion.
Free (continues to vibrate after outside energy stops) - A vehicle antenna
or seatback continues to vibrate after the energy stops.
A vibration in a tire and rim assembly can be caused by:
|| Change in Sidewall Stiffness (Force Variation)|
|| Rim Bent/Out-of-Round|
|| Tire Out-of-Round|
|| Wheel to Axle Mounting Error*|
|| Brake Component Wear or Failure*|
|| Drive Train or Engine Component Wear or Failure*|
|| Vehicle Component Characteristics*|
|| Combination of Some or All Factors|
* Factors not detected by the GSP9700 Vibration Control System.
1st order vibrations occur once per revolution (cycle) as
2nd order vibrations occur twice per revolution as illustrated
3rd order vibrations occur three times per revolution as illustrated