The article presents the tribological results of laboratory applications five selected thin hard coating on the three materials used in the manufacture of gears. Based on their evaluation in terms of scratch test nanohardness, coefficient of friction, wear resistance, coating thickness and its structure was DLCI coating applied to the gear of the C-C gearing made of material C60E. Thus coated wheels lubricated with organic oils Biohyd MS46 and BioGear S150 were tested for scuffing to the Niemann´s stand. The test results showed that due to the specific conditions for mating gears is not possible to design a coating for gear based on laboratory tests only, but should be based on what the specific requirements for the gear to be applied coating, ie. what type and kind of gearing and on what material wheels.
