OOSC, Part II, Item 10. Tires, b. - Tires with Exposed Cords

Based on information received from the Technology Maintenance Council (TMC) of ATA, Tire & Wheel Study Group (S.2), the following amendment to item 10 is suggested. They are concerned about some confusion that has resulted from the current OOSC, as well, they want to protect the motoring public from unsafe tires on commercial vehicles and ensure that the tire conditions that are truly hazardous warrant shutting a vehicle down. They feel that cords exposed in the sidewall area that are exceeding 2 square inches should be removed from the current dual tire application OOS condition and should be out-of-service on its own.

To clarify their changes, here is their reasoning. They feel that any vehicle equipped with one or more tires that has a noticeable air leak (condition 1), observable bump (condition 2), comes in contact with the vehicle (condition 3), whose weight carried exceeds the tire load limit (condition 4), has 75% of its tread missing in excess of 12 inches (condition 5) or has its plies exposed in an area that exceeds 2 square inches in the sidewall should be shut down until the tire(s) is (are) replaced. These are extremely hazardous conditions and could result in an imminent tire failure. However, tires that have exposed cords in the tread (which has 3-4 steel belts in addition to the casing plies) or worn treads that are less than 1/32 inch are not as dangerous by themselves. However, if you pair these conditions up and have two tires on an axle end that are worn down past than 1/32 inch, or two tires with exposed plies in the tread area on an axle end, or a worn tire paired with another with exposed plies in the tread, then you have a serious condition that could pose an imminent hazard. When two tires with any of these conditions are paired in a dual application, then the vehicle should be placed out-of-service.

Update the amendment made during the Louisville, KY meeting by adding the two OOS conditions to the automatic OOS section and amend the dual application section. This would result in the following amendment:(6) In a Radial tire when plies are exposed and the area exceeds 2 square inches (12.9 sq. cm) in the sidewall.(7) In a Bias Ply Tire: When ply cords are exposed in the sidewall and the area exceeds 2 square inches (12.9 sq.cm)For subsections (8),(9), and (10) for item 10.b., on dual tires, both tires must meet one or more of the conditions listed in item 10.b..(8) Bias Ply Tire: When more than one ply is exposed in the tread area and the exposed area of the top ply exceeds 2 square inches (12.9 sq.cm) or damaged plies are evident in the sidewall up to 2 square inches (12.9 sq .cm.).(9) Radial Ply Tire: When two or more plies are exposed in the tread area and the exposed area of the top ply exceeds 2 square inches (12.9 sq.cm) or damaged cords are evident in the sidewall up to 2 square inches (12.9 sq.cm.).(10) So worn that less than 1/32 inch (.8mm) tread remains when measured in any two adjacent major tread grooves (typically any groove containing a tread wear indicator) at 3 separate locations on the tire. Measurements should not be made on stone ejectors or tread wear indicators).