Vibration and Roughness

WARNING: Make sure the tires are deflated to their correct pressures after this check is completed.

Vibration, roughness, tramp, shimmy and thump may be caused by excessive tire or wheel runout, worn or cupped tires, or wheel and tire imbalance.

These conditions may also be caused by rough or undulating road surfaces. Driving the vehicle on different types of road surfaces will indicate if the road surfaces are actually causing the conditions.

Do not immediately suspect the tires when attempting to diagnose a vibration concern. Other sources of vibration include:
^ Loose or worn front wheel bearing.
^ Loose or worn suspension or steering components.
^ Excessive front brake disc runout.
^ Loose engine or transaxle supports.
^ Engine driven accessories.

A thumping noise usually means that the tire has flat or soft spots making a noise as they slap the roadways. Tire whine can be distinguished from axle noise because axle noise diminishes or changes according to load or speed. Tire noise remains the same over a range of speeds.

To verify that tire noise is not associated with shake or vibration, over inflate the tires one at a time and check for a change in the sound. The pitch or whine will change as the increased pressure changes the tire frequency.