Wheels and Tires: Testing and Inspection

DIAGNOSIS





Irregular and Premature Wear

Irregular and/or premature wear has many causes. Some of them are incorrect inflation pressures, lack of tire rotation, poor driving habits or improper wheel alignment. Incorrect inflation is common cause of tire premature wear.

NOTICE: Due to their design, radial tires tend to wear faster in the shoulder area, particularly on the front tires. This makes regular rotation especially necessary. After rotation, be sure to check wheel nut torque, and set tire pressures.

Tire Rotation





Tire rotation is recommended to equalize wear for longer tire life.
If the following conditions are noted, rotate the tires:
- Front tire wear is different from rear.
- Uneven wear exists across the tread of any tire.
- Left and right front tire wear is unequal.
- Left and right rear tire wear is unequal.
Check wheel alignment if the following conditions are noted:
- Left and right front tire wear is unequal.
- Wear is uneven across the tread of any front tire.
- Front tire treads have a scuffed appearance with "feather" edges on one side of the tread ribs or blocks.

NOTICE: Do not include temporary spare tire assembly in rotation.

Tread Wear Indicators





The original equipment tires have built-in tread wear indicators(l) to show when tires need replacement. These indicators may appear as wide bands. When the indicators appear in two or more grooves at three locations, tire replacement is recommended.

Inflation of Tires





Tire pressure, in cold condition (after vehicle has set for three hours or more, and driven less than one mile), should be checked monthly or before any extended trip. Tire pressure increases approximately 15% when the tires become hot during driving. Tire pressure specification is shown on the label located on the left door lock pillar.

NOTICE: Check the tire pressure whenever irregular wear is found. Tire inflation greatly affects tire wear. If the alignment check does not reveal any alignment problems, check the condition of the shock absorbers and wheel/tire balance.

Diagnosis List

If the following conditions are noted, rotation is required.
1. Front tire wear is different from rear.
2. Uneven wear exists across the tread of any tire.
3. Left and right front tire wear is unequal.
4. Left and right rear tire wear is unequal.

If the following conditions are noted, check the wheel alignment.
1. Left and right front tire wear is unequal.
2. Uneven wear exists across the tread of any tire.
3. Front tire treads have scuffed appearance with "feather" edges on one side of tread ribs or blocks.
4. There is cupping, flat spotting etc.

Higher than recommended pressure can cause:
1. Hard ride.
2. Poor steering stability.
3. Rapid and uneven wear at center of the tread.

Lower than recommended pressure can cause:
1. Tire squeal on turns.
2. Hard steering.
3. Rapid and uneven wear on the edges of the tread.
4. Tire rim bruises and rupture.
5. Tire cord breakage.
6. High tire temperatures.
7. Reduced handling.
8. Reduced fuel economy.

Unequal pressure on same axle can cause:
1. Uneven braking.
2. Steering lead.
3. Reduced handling.
4. Swerve on acceleration.

Radial Tire Waddle





Waddle is side-to-side movement at the front and/or rear of the car. It can be caused by the steel belt not being straight within the tire, or by excessive lateral runout of the tire or wheel. It is most noticeable at low speed, about 8 to 48 km/h (5 to 30 mph). It may also cause rough ride at 80 to 113 km/h (50 to 70 mph).
The car can be road tested to see which end of the car has the faulty tire. If the tire causing the waddle is on the rear, the rear end of the car will "waddle". From the driver's seat, it feels as if someone is pushing on the side of the car.
If the faulty tire is on the front, the waddle is more easily seen. The front sheet metal appears to be moving back and forth. It feels as if the driver's seat is the pivot point in the car.
Another more time-consuming method of determining the faulty tire is substituting tire and wheel assemblies that are known to be good. Follow these steps:
1. Drive the car to determine if the waddle is coming from the front or rear.
2. Install tire and wheel assemblies known to be good (from a similar car) in place of those on the end of the car which is waddling. If the waddle cannot be isolated to front or rear, start with the rear tires.
3. Road test again. If improvement is noted, install the original tire and wheel assemblies one at a time until the faulty tire is found. If no improvement is noted, install tires known to be good in place of all four. Then, install the originals one at a time until the faulty tire is found.

Radial Tire Lead/Pull

"Lead/Pull" is vehicle deviation from a straight path, on a level road with no pressure on the steering wheel.
Lead is usually caused by:
1. Poorly manufactured radial tires.
2. Uneven brake adjustment.
3. Wheel alignment.
The way in which a tire is built can produce lead in a car. 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.
The "Radial Tire Lead/Pull Correction" chart should be used to make sure that front wheel alignment is not mistaken for tire lead.
Rear tires will not cause lead/pull.

Radial Tire Lead/Pull Correction Chart





Typical examples of abnormal tire ahead wear and major causes:

CAUTION: Similar wear patterns can be caused by worn suspension parts, misalignment of wheels and tires, and other suspension related problems.





Spotty wear - wear localized on shoulder sections, and in an extreme cases, the tire becomes polygonal in shape
1. Tire or wheel out of round or distorted.
2. Hub or knuckle out of round or distorted.
3. Play in hub bearings or ball joint.
4. Rotating parts out of balance.





Tread wear one-sided.
1. Rotating parts out of balance.
2. Tire or wheel out of round.
3. Hub or knuckle out of round or distorted.





Localized tread wear.
1. Once spotty wear develops in tread due to hard braking, localized wear tends to be promoted.





Shoulder wear (generally wear develops in outer shoulder):
1. Camber or toe-in incorrect.
2. Shoulder wear caused by repeated hard-cornering.





Wear in shoulders at points opposed to each other.
1. Tire or wheel out of round or distorted.
2. Play in bearings or ball joint.





Premature wear in shoulders.
1. Flexing of tire excessive due to under-inflation.





One sided feather edging.
1. Wear caused by repeated hard-cornering.
2. Camber or toe-in incorrect.