Symptom Related Diagnostic Procedures

Tire Diagnosis - Irregular or Premature Wear

Irregular or premature tire wear has many causes.




- Incorrect inflation pressure may cause irregular or premature tire wear
- Lack of regular rotation may cause irregular or premature tire wear.




- Driving habits may cause irregular or premature tire wear.




- Improper wheel alignment may cause irregular or premature tire wear.

Inspection Procedure

1. Inspect the front tire wear. Inspect the rear tire wear.
2. Rotate the tire if any of the following conditions are evident:
- Uneven wear exists across the tread of any tire.
- The left side tire wear and the right side tire wear is unequal.
- A scheduled maintenance interval.
3. Perform a wheel alignment if the following conditions exist:
- The left side and/or the right side front tire wear is unequal.
- The wear is uneven across the tread of the tire.
- The tire treads have a scuffed appearance with feather like edges on 1 side of the tread ribs or the blocks.

Tire Diagnosis - Waddle Complaint




Tire waddle is a side to side movement at the front of the vehicle and/or the rear of the vehicle. The waddle can be caused by the following conditions:
- A steel belt not being straight within the tire (broken or shifted belt)
- Excessive lateral runout of the tire
- Excessive lateral runout of the wheel
The waddle is most noticeable at a low speed of about 8 - 48 km/h (5-30 mph). The waddle may appear as ride roughness at 80 - 113 km/h (50-70 mph). The waddle may appear as a vibration at 80 - 113 km/h (50-70 mph).

Inspection Procedure

1. Raise the vehicle.
2. Support the vehicle with safety stands.
3. Perform the following preliminary inspection:
1. Wear gloves when inspecting the tires in order to protect against the possibility of the steel belts sticking through the tire.
2. Index mark the tire with a crayon in order to note the start and the stop position.
3. Rotate each tire and wheel by hand.
4. A broken or shifted belt will appear as a twist or a bump in the tread.
4. You may use tire substitution in order to identify the faulty tire. Perform the following steps for a tire substitution check:
1. Use a comparable tire in order to replace each tire, 1 at a time.
2. Test drive the vehicle.
3. You will eliminate the problem when you remove the faulty tire from the vehicle, if the problem is tire and/or wheel related.

Radial Tire Lead/Pull Correction

Steps 1 - 2:

Steps 3 - 9:

Lead/pull is the deviation of the vehicle from a straight path on a level road with no pressure on the steering wheel. Lead is usually caused by the following conditions:
- Poor tire construction
- Uneven brake assemblies
- Improper tire and wheel alignment In the front tires (rear tires will not cause lead)
Tire construction can be a cause of lead in a vehicle. An example of this is placement of the belt. off center belts on radial tires can cause the tire to develop a side force while rolling straight down the road, and the tire will tend to roll like a cone.
Use the lead/pull correction table in order to verify that improper tire and wheel alignment is not mistaken for tire lead.