Rims/Tires - Vibration Diagnosis
CATEGORYSuspension
SECTION
7
PAGE
8
ISSUE
05/94-0460
CODE
700
Subject:
Addressing Vibration Complaint Caused By Rims or Tires
Application:
All Models
Vibration complaints must be carefully diagnosed and corrected so that the customer does not have to return for a second or third attempt. This bulletin contains information on rims and tires to assist you in identifying the root cause of a complaint and making an adjustment or repair. Also see PSI 04/94-0457 for information regarding steering wheel oscillation.
Interview the customer
Explore the answers in order to make the proper adjustments. recommendations or repairs. Take notes! Some sample questions are listed below:
^ At what outside temperature range does the symptom occur?
^ At what road speed does it occur?
^ When was the symptom first noticed?
^ Can the symptom be duplicated?
^ Is the symptom intermittent?
^ Does it occur after the car has been parked several hours and then disappear after a few miles?
^ Have there been any previous attempts at a repair?
Preliminary Checks
1. Test drive the car and verify the customer complaint. Flat spots from sitting should disappear after a few miles.
2. Check that the correct type of tire and rim are fitted to the car.
3. Inspect the tires and rims for visible damage.
4. Make sure that tire pressures are correct and the same as those shown in the owner's manual.
5. Inspect the tires for unusual wear patterns.
6. Check that there are no flat areas on the tire tread.
7. Check the rims for dents or flat spots.
8. Check for missing wheel weights.
Balancing Tires
1. Remove and dynamically balance all four tires.
NOTE
Modern balance machines have settings for "high accuracy". Be sure and use this feature when fine-tuning the balance. If you do not, the machine may round off a weight of less than 1/4 oz. to zero.
2. During the balance process, observe the rotation of the tire and rim. There should not be any flat spots in the tire or rim nor should there be any lateral runout. If a tire has flat spots or lateral run-out, replace it. If a rim has damage or lateral run-out, replace it.
NOTE
^ If the car is equipped with full wheel covers and vibration still exists, remove the wheel covers and test drive again. If the vibration goes away, replace the suspect wheel covers.
^ If excessive weight is required, it may be necessary to dismount the tire, rotate it 180° on the rim and rebalance.
^ Certain balance machines have "match mounting" capability which matches a rim and tire before balancing takes place. See Figure 2.
^ Always use tire lubricant when mounting a rim or tire. Do not use petroleum-based products. See Figure 3.
3. Road test the car. Try to best duplicate the conditions when the complaint occurs.
NOTE
If additional remedies are necessary, there may be damage or runout at the rim.
Checking Rims for Runout or Damage
1. Dismount the tire and install the rim on the balance machine. Spin the rim by hand and observe the areas where the tire and rim meet.
2. If no runout or damage is visually detected. mount the rim (without the tire) in a stationary wheel balancing machine. Set up a dial indicator gauge with a pointer and measure both the radial (out-of-round) and axial (warp) tolerances on both sides of the rim. See Figure 4.
Maximum permitted tolerance:
Rim type: [A] radial (mm) [B] axial (mm)
Steel rim 0.6 0.8
Alloy 0.5 0.5
3. Replace any rim that has excessive tolerances.
NOTE
Even new rims should be inspected prior to mounting a tire to make certain there is no transport damage.
Warranty Information:
Based on a customer complaint. a claim may be submitted only when a manufacturing defect is clearly demonstrable.
Based on a specific condition, however. you may contact your District Service & Parts Manager for authorization.