Wheels/Tires - Steering Wheel Vibration/Oscillation: Overview
44 Steering wheel shimmy, vibration and/or oscillation44 10 02
2022563/2
May 18, 2010
Supersedes Technical Service Bulletin Group 44 number 10-01 dated January 27, 2010 for reasons listed below.
Affected Vehicles
Condition
Complaints of steering wheel vibration and/or steering wheel oscillation while driving at highway speeds.
This condition does not result in any handling concerns or loss of vehicle control.
Technical Background
The above stated conditions may be caused by the following:
^ Imbalanced wheel and tire assembly.
^ Tires with high road force values.
EXPLANATIONS AND DEFINITIONS
Radial force variation
The radial force is the force with which a tire is compressed.
Tires have softer and stiffer areas along their circumference. In Figure 2, the softer and stiffer areas are illustrated by different size springs.
If this wheel rolls on level road with constant wheel load (Figure 2, arrow 1), the center of the wheel rises and falls by the amount (x) because of the varying spring hardness. The change by the amount (x) can be felt in the vehicle as vibration or shaking of the steering wheel.
The change of the compression force of the tire is the radial force variation.
To measure the radial force variation, a constant force is applied to the tire on a vibration control unit (such as Hunter's VAS 6230 Road Force Measurement(R) System vibration control unit [GSP9700] or similar), and the tire is operated. This simulates the pull out of the tire on the road surface. The variation of the radial force is independent of the turning direction and is measured as the difference of maximum and minimal radial force (peak-to-peak value, or Total Indicated Reading [T.I.R.]).
On Audi vehicles the peak-to-peak value (T.I.R.) must be 27 lbs. or less.
Harmonic vibrations
The wheel force variations during the turn of the wheel can be mathematically divided into individual harmonic vibrations.
For an objective assessment of the tire stiffness, the first harmonic (the basic vibration) is used.
The basic vibration or first harmonic is the share of the radial force variation that causes the strongest vibrations.
On Audi vehicles the first harmonic (road force) must be 18 lbs. or less.
Production Solution
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Warranty
Tire warranty facts when submitting tire claims through the Audi Tire Warranty Assistance Program (ATAP)
The Audi Tire Assistance Program is not an Audi of America, Inc. factory warranty. Audi of America, Inc. does not warranty tires originally installed or sold as replacement for use on Audi vehicles. Individual tire manufacturers provide all the underlying tire warranties.
Dealer Tire
^ Tires are warranted through the specific tire manufacturer
^ Tire Coverage applicable per tire manufacturer guidelines
^ 0 to 6,000 miles 100% coverage at dealer net
^ 6,001 to 12,000 miles 50% coverage at current dealer net
What is eligible?
1. Tire tread depth must be no more than 2/32 of an inch (1.6). At 2/32 of an inch tread depth, the tire is considered worn to the limit.
2. A defect in material and workmanship is present.
3. Originally installed tires (original equipment tires) are on the vehicle for which they are designated.
4. Replacement tire(s) must be purchased through the Audi Tire Center.
5. The replacement tire(s) must have the same tire size, load rating, speed rating, and be the same tire model from the same tire manufacturer.
Ride disturbance
^ Ride disturbance cases include out-of-round, excessive vibration, and lateral/radial pull conditions
^ For most tire manufacturers, this condition is only covered if the tire has no more than 2/32-inch of wear from its maximum tread depth (1/32-inch for Bridgestone and Toyo brand tires)
^ Ride disturbance claims are eligible only if they are not a result of:
^ Poor tire maintenance
^ Temporary flat spotting (goes away after vehicle is driven for approximately 20 miles)
^ Out of balance conditions caused by outside influence
For all ride disturbance claims, it is required that proper diagnosis is followed and documentation is retained (e.g., balance data, road force measurement data)
What is not eligible?
Tire conditions, which are not eligible for the ATAP, include, but are not limited to:
1. Tires that have exceeded the time or mileage limits of the ATAP
2. Tire damage due to outside influence or road hazard (e.g., curb or pot hole damage), use of non-approved cleaning agents, or as a result of being used in a racing/competitive event
3. Tire damage/wear due to improper or lack of tire rotation, and/or incorrect vehicle alignment
4. Tires worn due to misuse or failure of another component
5. Tires worn down to or below 2/32 of an inch (to wear bars)
6. Over-inflated or under-inflated tires
7. Flat spotted tires due to brake lock-up
8. Replacement tires not purchased through the Audi Tire Store
9. Tires not approved for specific Audi models (e.g., Audi-approved A4 tire on an Audi A5)
10. Tires that have been modified (shaved, for example)
11. Tires injected with sealants, dry or liquid balancers
12. Tires with the U.S. Department of Transportation (DOT) identification number removed or rendered illegible
Other reimbursement questions or concerns
For any additional reimbursement questions or concerns outside of the above instructions, please contact your Audi claims specialist team.
Required Parts and Tools
Tools
^ Use VAS 6230 Vibration Control Tire Balancer or similar Road Force Measurements(R) System to check balance, Road Force values, and to make necessary adjustments.
^ Use centering hub in conjuction with VAS 6243 model-specific clamping plate (5 finger clamping device) or similar device to ensure proper mounting of wheel and to prevent damage to wheels.
^ Vetronix MTS 4100 NVH Analyzer is helpful when diagnosing vibration concerns and can help[ narrow down the list of possible sources of the vibration.
Additional Information
More information can be found in the following resources:
^ ELSAWeb: Wheel and Tire Guide >> Diagnosing and Testing
^ SSP: Noise, Vibration. and harshness 961403
The following repair procedure(s) will be necessary to complete this procedure:
^ Chassis >> Wheel and Tire guide >> Diagnosis and testing
All parts and service references provided in the TSB are subject to change and/or removal. Always check with your Parts department and service manuals for the latest information.
Tire Data Sheet
Vibrations and steering wheel oscillation
7.4 service mode Setup and Features
Programmed Road Force(TM) Limits