The following are some causes for irregular and premature wear:

Rotate the tire and wheel if the following conditions are noted:

Check the wheel alignment check if the following conditions are noted:

Built-in tread wear indicators are equipped on the original tires. The built-in tread wear indicators show when tires need replacement. The indicators appear in 6 places (every 60) around the tire when the tread is worn to 2/32 inch . Tire replacement is recommended when the indicators appear in 3 or more locations.

Waddle is a side to side movement at the front and/or at the rear of the vehicle. A steel belt not being straight within the tire can cause a waddle. A waddle is most noticeable at low speeds of 8-48 km/h (5-30 mph). A waddle may appear as a ride roughness at speeds of 80-113 km/h (50-70 mph). Road test the vehicle to see which end of the vehicle has the faulty tire. A rear waddle tire causes the rear of the vehicle to shake from side to side or to waddle. From the driver's seat it feels like someone is pushing on the side of the vehicle. The front hood assembly appears to move back and forth in a front waddle tire. The driver feels as though he is at the pivot point. Use a Tire Problem Detector (TPD) to detect a waddle. The TPD is a roller drum that slowly rotates the tire on the vehicle while under load (checking the spindle vibration). The following common method is often used to determine the faulty tire by substituting a known good tire/wheel assembly:

1. Road test the vehicle to determine if the waddle is coming from the front or the rear.

Install tire and wheel assemblies known to be good (on similar vehicle) if the place of those on the offending end.

Important: Refer to if the vehicle is equipped with the Tire Pressure Monitoring System (TPMS).

2. Road test the vehicle again.
3. If improvement is noted install the original tire and wheel assemblies one at a time until the faulty tire is found.

Lead Pull is the deviation from a straight path on a level road with no pressure on the steering wheel. The following are common causes of Lead Pull:

The way in which a tire is built can produce lead. An example if the placement of the belt. An off center belt on radial tires causes the tire to develop a side force while rolling straight down the road. The tire tends to roll like a cone. Use the Radial Tire Lead/Pull Correction chart to make sure that the wheel alignment is not mistaken for tire lead. Rear tires usually do not cause lead/pull.

Imbalance or runout can cause tire or wheel induced vibrations.

Low-speed vibrations (those less than 40 mph) usually are runout related. Highway speed vibrations (those above 40 mph) can be caused by either imbalance or runout.

The numbers below refer to the numbers in the VIBRATION COMPLAINT CHART.

1. Road test the vehicle to verify the complaint.
2. Perform a careful visual inspection for the following:

•	Inspect for obvious tire and wheel runout.

•	Inspect for obvious drive axle or propeller shaft runout.

•	Inspect for proper inflation pressure.

•	Inspect for wrong trim height.

•	Inspect for bent wheels.

•	Inspect for debris build-up on the tire or wheel.

•	Inspect for loose or missing wheel weights or wheel nuts.

•	Inspect for irregular or excessive tire wear.

•	Inspect for proper tire bead seating on the rim.

•	Inspect for the following for tire damage:

•	Inspect for tread distortions.

•	Inspect for tread separations.

•	Inspect for tread bulges from impact damage. Slight sidewall indentations are normal. Slight sidewall indentations do not affect the ride quality.

3. Perform a balance procedure if vibrations occur at high speeds. A balance procedure is the easiest procedure to perform. Perform an off-car two-plane dynamic balance first. An off-car two-plane dynamic balance will correct any imbalance in the tire and wheel assembly. If the off-car two-plane dynamic balance does not correct the highway speed vibration, the probable cause is excessive runout. The following can cause runout:

•	The tire can cause runout.

•	The wheel can cause runout.

•	The way the wheel attaches to the car can cause runout.

4. Runout is the probable cause of low speed vibrations. Measure the free runout of the tire and wheel assembly. Use a dial indicator with a roller wheel if available. A dial indicator with a button end may be used. Measure lateral runout (side to side) on the tire's sidewall as close to the read shoulder as possible. Measure radial runout (up and down) on the center tread rib. Some tread designs require tightly wrapping a piece of tap around the center tread circumference for a better dial indicator contact. Refer to to measure wheel runout. Disregard any instantaneous indicator needle jumps due to sidewall depressions, tread block, etc. when measuring radial and lateral runout. Record total indicator reading. Record the location of the high point of the runout. The total tire and wheel on-car runout should be less than 1.5 mm (0.060 in). Go to Step 5 if either measurement exceeds 1.5 mm (0.060 in).
5. Mount the tire and wheel assembly on a dynamic balance machine. Measure the amount of runout. Locate on the machine by the wheels inside the center pilot hole. Use the same procedure as in Step 4 to record the amount of tire runout and its high point location. Refer to Replace the wheel if it exceeds specifications. If the tire and wheel radial runout or the tire and wheel lateral runout exceeds 1.27 mm (0.050 in) at the tire tread perform the following procedure:

5.1.	Break down the tire and wheel assembly.

5.2.	Rotate the tire on the rim 180 degrees.

5.3.	Refer to if the vehicle is equipped with TPMS.

5.4.	Reinflate the tire.

5.5.	Mount the tire on the dynamic balance machine.

5.6.	Measure and record the radial and the lateral runout and its location.

5.7.	Replace the tire if the following conditions exists:

•	If the radial runout still exceeds 1.27 mm (0.050 in).

•	If the lateral runout still exceeds 1.27 mm (0.050 in).

•	And if the high point has moved approximately 180 degrees (following the tire around the rim).

5.8.	Rotating the tire in many cases will bring the assembly into the acceptable range of less than 1.27 mm (0.050 in).

6. The attachment of the tire and wheel assembly to the hub is the probable cause if the runout of the tire and wheel assembly is within limits when measured off the car, but exceeds the limits when measured off the car. Rotate the tire and wheel assembly two wheel studs. Recheck the runout. Several positions may have to be tried to find the best location. Proceed to Step 7 if the tire and wheel assembly runout cannot be reduced to an acceptable level.
7. Remove the tire and wheel assembly. Use a dial indicator to measure the wheel stud runout. Zero the dial indicator button on one stud. Lift button gently off stud. Rotate the flange to position next stud against the dial indicator button. Record the runout on all studs. The dial indicator should read zero when repositioned on the first stud that was checked. Replace the hub if the runout exceeds 0.76 mm (0.030 in).
8. An on-vehicle finish balance may be required. An on-vehicle finish balance will correct any imbalance in the tire and wheel assembly. An on-vehicle finish balance will correct any brake rotor imbalance. An on-vehicle finish balance will correct any hub cap imbalance.