This practice fulfills the need for a standardized system for identifying and describing the tread pattern features of tires that are characteristic of intermediate states of treadwear short of total wear out. This descriptive capability is especially important in testing programs devoted to the development of improved performance tires. It is also important in assessing and evaluating tires after periods of typical tire usage.

1.1 This practice provides the instructions and nomenclature to evaluate the wear features of the tread pattern on a tire for some intermediate state short of total wear out.

1.2 A tire may be characterized by certain worn tread pattern conditions that are collectively referred to as "irregular wear" features. Definitions for these features are given in a special logical and conceptual sequence. First, basic tread pattern definitions are given. Then, additional tread pattern definitions directly related to the basic tread pattern definitions are given. Understanding these secondary definitions requires the knowledge of the basic definitions.

1.3 Based on the terms of this developed system of tread pattern definitions or descriptions, a set of treadwear descriptions is presented that encompasses both regular wear and irregular wear features.

1.4 This hierarchical arrangement produces the accurate and concise definitions needed to evaluate the complex irregular wear conditions of tires.

1.5 See Fig. 1 for tread pattern features or characteristics. See Fig. 2 and Fig. 3 for typical illustrations of regular or uniform and irregular treadwear features.