Tires: Testing and Inspection

PRESSURE GAUGES
A quality air pressure gauge is recommended to check tire pressure. After checking the air pressure, replace valve cap finger tight.

TREAD WEAR INDICATORS

Fig. 2:

Tread wear indicators are molded into the bottom of the tread grooves. When tread depth is 1.6 mm (1/16 inch), the tread wear indicators will appear as a 13 mm (1/2 inch) band.

Tire replacement is necessary when indicators appear in two or more grooves or if localized balding occurs.

TIRE WEAR PATTERNS
Under inflation will cause wear on the shoulders of tire. Over inflation will cause wear at the center of tire.

Tire Wear Patterns:

Excessive camber causes the tire to run at an angle to the road. One side of tread is then worn more than the other.

Excessive toe-in or toe-out causes wear on the tread edges and a feathered effect across the tread.

TIRE NOISE OR VIBRATION
Radial-ply tires are sensitive to force impulses caused by improper mounting, vibration, wheel defects, or possibly tire imbalance.

To find out if tires are causing the noise or vibration, drive the vehicle over a smooth road at varying speeds. Note the noise level during acceleration and deceleration. The engine, differential and exhaust noises will change as speed varies, while the tire noise will usually remain constant.

Lead Correction Chart:

LEAD CORRECTION CHART
Use the following chart to diagnose a vehicle that has a complaint of a drift or lead condition. The use of the chart will help to determine if the lead condition is the result of a bad tire or is caused by the front wheel alignment.