Wheels/Tires - Vibration and Road Shake At 45-65 Mph

88chrysler01

Models


1986-1988 All Domestic & Import Cars & Trucks


Subject


Vibration & Smooth Road Shake at 45-65 MPH


Index


TIRES & WHEELS


Date

December 21, 1987

No..


22-01-87 (C01-22)

P-4641
SYMPTOM/CONDITION

Vibration and/or smooth road body shake at 45-65 MPH. Condition could occur during acceleration, coast, or at road load conditions.

DIAGNOSIS

Road test the vehicle and check for vibration and/or shake at various highway speeds.

REPAIR PROCEDURE

If the above condition is noted, then it will be necessary to check tire and wheel runout and balance per the following procedure.

1. Check tire and wheel balance and assembly runout on a properly calibrated off-car tire balancer as outlined in the appropriate service manual. If the assembly exceeds .040" lateral and radial runout, then it will be necessary to match mount the tire to the wheel according to the match mounting section of this bulletin.

2. If lateral and radial runout is less than .040", then continue to rebalance the tire and wheel assembly. Reinstall the tires and wheels and road test the vehicle. If vibration is still evident, it will be necessary to perform an on-car balance to fine tune the tire and wheel assemblies to the vehicle.

NOTE: IF THIS IS REQUIRED, ADVISE THE CUSTOMER THAT REBALANCING MAY BE NECESSARY WHENEVER THE TIRES ARE ROTATED.
3. In extreme cases on a sensitive vehicle, the above balance procedure may not eliminate all of the vibration, even though tire and wheel assembly runout is less than .040". In these cases it will be necessary to perform the match mounting procedure to further reduce force variation in the tires.

Use the following procedure to match mount the tires to the wheels.

Match mounting is a technique used to reduce radial or lateral runouts on tire/wheel assemblies. Excessive runout is a source of ride complaints and match mounting can be used to minimize the runout.

DIAGRAM 1:

Tire to Wheel Hatch Mounting Procedure

First determine the runout which needs to be minimized. If radial runout is the problem, take a measurement on the center tread rib (this is normally a solid rib, easy to measure, and normally indicative of what the tire as a whole is like; but, keep in mind that any rib with excessive runout can cause a problem). If lateral runout is the problem, take a measurement on the sidewall just below the edge of the shoulder tread pattern. Record the runout magnitude and put a crayon mark at the high spot location on the tire and also on the wheel (see Diagram #1).

DIAGRAM 2:

Take the assembly to the tire mounting machine. Put a reference crayon mark on the tire sidewall at the valve location. Break the assembly down and rotate the tire 180~ (half way around) on the rim so that the valve reference mark is opposite the valve stem (see Diagram #2). Reinflate the tire and measure the runout in question. Record the magnitude and mark the high spot location on the tire.
If the runout is reduced below acceptable guidelines, you have solved the problem. If the runout is still excessive, you will do one of the following three (3) procedures:

a. If the high spot is within 4" of the first high spot on the tire and is still outside of guidelines, replace the tire.

b. If the high spot is within 4" of the first high spot on the wheel, the wheel may be out of tolerance. Remove the tire and check the wheel for runout.

DIAGRAM 3:

c. If the high spot is not within 4" of either original high spots on the tire or wheel, then draw an arrow from the second high spot to the first high spot (in the shortest direction - see Diagram #3) and rotate the tire on the rim 90~ (1/4 turn) in that direction. This will normally reduce the runout to an acceptable figure.

In the majority of cases, the first 180~ turn of the tire will either fix the problem or indicate which item to replace.
POLICY: Reimbursable within the provisions of the warranty


TIME ALLOWANCE:
Labor Operation No. 22-40-02-90 - 1986-1988 . . . . . . . . . . . . . . . 0.5 Hrs.
Balance Both Front Wheels

22-40-02-91 - 1986-1988 . . . . . . . . . . . . . . . 0.5 Hrs.
Balance Both Rear Wheels

22-40-01-90 - 1986-1988 . . . . . . . . . . . . . . . 0.6 Hrs.
Match Mount Tire to Wheel and Balance-One

Above on all Domestic and Import Cars and Trucks


FAILURE CODE: 73 - Out of Balance