Ostermeyer, G. and Perzborn, N., "Test-Variability of Tribological Measurements," SAE Technical Paper 2012-01-1805, 2012, doi:10.4271/2012-01-1805.
For brake performance measurements, many standardized test procedures and machines were developed. A characteristic problem of these highly complex machines is the occurrence of measurement uncertainties, which usually are not predictable and rather difficult to explain. One part of explanations is driven by the huge but not yet complete list of influencing factors for the high load friction processes. Another part of explanations is given by f.i. manufacturing tolerances, load histories of machines and specimens and so on. A systematic investigation of these influences is very time-consuming and could be difficult to realize on professional test-machines .On the other hand, simple laboratory tribometers are rather good for sensitivity investigations in principle but the friction systems are too far from the real system. Closing the gap between classical pin-on-disk tribometers and high performance test machines in the brake industry, a special high-load-tribometer  has been developed. It combines high load friction processes with the simplicity of a pin-on-disc test machine.This machine is used to investigate sensitivities of the tribology of brake pads systematically. This paper demonstrates dependencies of specimen geometry, friction radius and brake discs temperature.