5.1 The resistance of leather to abrasion, as measured on a testing machine in the laboratory, is generally only one of several factors contributing to wear performance or durability as experienced in the actual use of the material. While "abrasion resistance" (often stated in terms of the number of abrasion cycles) and "durability" are frequently related, the relationship varies with different end uses and different factors may be necessary in any calculation of predicted durability from specific abrasion data. This test method provides a comparative ranking of material performance, which can be used as an indication of relative end-use performance.

5.2 The resistance of leather to abrasion may be affected by factors including test conditions; type of abradant; pressure between the specimen and abradant; mounting or tension of the specimen; and type, kind, or amount of finishing materials.

5.3 Abrasion tests utilizing the rotary platform abraser may be subject to variation due to changes in the abradant during specific tests. Depending on abradant type and test specimen, the abrasive wheel surface may change (that is, become clogged) due to the pick up of finishing or other materials from test specimens. To reduce this variation, the abrasive wheels must be resurfaced at regularly defined intervals.

5.4 The measurement of the relative amount of abrasion may be affected by the method of evaluation and influenced by the judgment of the operator.