Radial Force Variation
Radial Force Variation can be checked using the Hunter GSP 9700 Vibration Control System (Wheel Balancer) or equivalent, if available. This type of equipment helps to correct ride disturbances by reducing the radial force variation of an assembly through re-indexing of the tire to wheel.
The equipment manufacturer or DaimlerChrysler Corporation may supply reference values as guidelines. Radial force measurements above the reference value may not always result in a ride disturbance, nor do they automatically mean the assembly components are out of specification. Do not replace components based on radial force values alone. Balancing, runout diagnosis, re-indexing, and subjective road testing must be performed as outlined in previous sections of this diagnosis and testing procedure.
Use the Radial Force equipment to identify suspect assemblies and minimize the radial forces. After all suspect assemblies are optimized, reinstall the assemblies and road test the vehicle. If a disturbance still exists and all other vibration diagnostic procedures have been completed, replace one tire or one wheel at a time, starting with the assembly having the highest force variation. Be sure to minimize each new assembly. Road test the vehicle following each replacement. Continue this process until the disturbance is resolved.
| MEASUREMENT | 17 INCH TIRES | 18 INCH TIRES | 20 INCH TIRES |
| Total Radial Force Variation (RFV) | Less Than 25 Lbs. ± 2 Lbs. | Less Than 18 Lbs. ± 2 Lbs. | Less Than 23 Lbs. ± 2 Lbs. |
| Radial First Harmonic (R1H) | Less Than 12 Lbs. ± 2 Lbs. | Less Than 12 Lbs. ± 2 Lbs. | Less Than 15 Lbs. ± 2 Lbs. |
| Radial Second Harmonic (R2H) | Less Than 8 Lbs. ± 2 Lbs. | Less Than 8 Lbs. ± 2 Lbs. | Less Than 10 Lbs. ± 2 Lbs. |