Debris on runways and in parking areas causes tire failures, and results in many tires being removed long before they reach full service life. It is important that those areas be kept clean at all times. When you ground handle an aircraft, do not pivot with one wheel locked or turn sharply at slow speeds.

You should make every effort to prevent oil, grease, hydraulic fluid, or other harmful materials from coming in contact with the tires. When there is a chance that harmful materials may come in contact with the tires during maintenance, they should be protected by covers. To clean tires that have come in contact with oil, grease, or other harmful material, you should use a brush or cloth saturated in a soap and water solution. Rinse well with tap water.

If a tire shows signs of uneven or excessive tread wear, the cause should be investigated and the condition remedied before the tire is ruined. Some of the common causes of uneven tread wear are

Figure 11-28.Rapid tread wear caused by misalignment.

underinflation, overinflation, misalignment, and incorrect balance.

UNDERINFLATION. Underinflation causes the tire to wear rapidly and unevenly at the outer edges of the tread, as shown in figure 11-26. An underinflated tire develops higher temperatures during use than a properly inflated tire. This can result in tread separation or blowout failure.

OVERINFLATION. Overinflation reduces the tread contact area, causing the tire to wear faster in the center, as shown in figure 11-27. Overinflation increases the possibility of damage to the cord on impact with foreign objects and arresting cables on the runway or flight deck.

MISALIGNMENT. Figure 11-28 shows rapid and uneven tire wear caused by incorrect camber or toe-in. The wheel alignment should be corrected to avoid further wear and mechanical problems.

BALANCE. Correct balance of the tire, tube, and wheel assembly is important. A heavy spot on an aircraft tire causes that spot to always hit the ground first upon landing. This results in excessive wear at the one spot and an early failure at that part of the tire. A severe case of imbalance may cause excessive vibration during takeoff and landing. This makes handling of the aircraft difficult.