Porsche 928 - WORKSHOP MANUAL 1977 Workshop Manual page 117

44
Wheels, Tires, Alignment 928
Wheel balancing
General
If the wheels are too unbalanced. this not only causes vibrations and shaking of the steering wheel
but also results in higher wear on various chassis components.
Even if wheels are balanced correct/y, uneven running and steering can be caused by excessive
geometry faults (radial and lateral run-out) and irregularities in tires, e.g. material accumulating in one
place (when rolling under diverse suspension conditions).
Extreme care, compliance with instructions and procedures, as well as the attempt to remedy even
the last gram of imbalance is necessary to achieve a good result.
Notes I prerequisites
Wheel suspension elements must be technically sound
Wheels must be cleaned, without any foreign bodies in the tires.
- Check radial and lateral run-out on wheels without flat spots with a radial run-out measurement
gauge, e.g. VAG 1435. Tfy fo achieve values of less than 1 mm and greater rhan 0.5 mm.
-Tires must be matched to achieve minimum out-of-true characteristics or to optimize smooth run-
ning. Tips and information on this as well as tire mounting paste can be found on Page 44 7/8
- If disk wheels (rims) run absolutely true but there is extreme radial and lateral run-out (caused by
braking flat-spots, cord breaks, other damage) replace the tire if necessary.
- On/y balance used wheels when warm as f/at spots may orherwise simulate an imbalance. Never
match in the case of flat spots.
- The correct tire pressure is a crucial prerequisite
- Use self-adhesive or clamp weights according to the type of disk wheel. Use self-adhesive weights
for cast light-alloy disk wheels.
Coated clamp weight for forged light-alloy disk wheels.
Notes on fitting the weights, see Page 44-17
44- 10
Wheel balancing
a
Printed in Germany-XX, 1988