The HFRR (High Frequency Reciprocating Rig) was used to measure diesel lubricity by rubbing a steel ball on a plate in a bath of fuel. The ball develops a flat spot over the course of the test which is called the wear scar, the diameter of which is the measure of diesel lubricity. All diesel sold in South Africa must pass this test with a maximum wear scar of 460 microns, which does ensure adequate lubricity for all diesel fuel systems. This is the same specification as applied in Europe and many other parts of the world. The results in Figure 1 represent the fuels tested as per Table 1.