WM, 440594 Balancing/Optimizing Wheels: Information
Excessive rough running of the wheels, caused by wheel imbalance, flat spots and misshapen tire structures causes vibrations and shaking in the steering wheel. This in turn leads to increased wear on various parts of the chassis.
Even if wheels are correctly balanced, rolling and steering imbalance can still occur. For example with:
- Excessive geometric errors (radial and lateral runout)
- Radial force variations (softer and more rigid areas in the tire)
Recommendations/requirements
Information
- Achieving a good result requires utmost care, observance of instructions and procedure, and attempting to eliminate even the very last gram of imbalance.
Wheel suspension elements must be in good working order.
The wheels must be clean with no foreign objects in the tire.
Use a tire measuring gauge, e.g. > VAS 6079 - Dial gauge to check radial and lateral runout values on wheels without flat spots.
Values of less than 1 mm are desirable - around 0.5 mm would be better.
To limit the number of radial runout errors and to optimize rolling smoothness, it is a good idea - and even necessary in some cases - to match the tire (i.e. to fit it at a favorable position with respect to the rim). Follow tips and fitting instructions as well as information on tire mounting paste for tires.
If the disc wheels (wheels without tires) are perfect but the complete wheels have large axial and radial runout values (due to ply breakage or other damage), it may be necessary to replace the tire.
Balance used wheels only after they have been warmed up by driving, otherwise flat spots will simulate imbalance. Never perform matching in the case of flat spots. In the event of flat spots, wheels must be warmed up by driving 25 - 30 km (16 - 20 miles) on a motorway. Lift up the vehicle immediately on return. This prevents new flat spots from forming.
Correct tire pressure is an important prerequisite.
Place the balancing weights at the prescribed position
When fitting the wheel to the wheel hub and brake disc, the contact surfaces must be clean (free of dirt).
On wheel balancing machines with vibration control system (> VAS 6230BE - Vibration Control System ), the radial force variation value must be set in the machine's basic settings as follows:
- Porsche Cayenne: 120 N
- All other models: 80 N