The tribological behaviour of soot was studied by means of a pin-on-disk tribometer coupled to a high-resolution wear measurement system (RNT). The soot particles were characterized by high-resolution transmission electron microscopy (HRTEM), energy electron loss spectroscopy (EELS), electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS). The surfaces of the tribometer disks were analyzed by atomic force microscopy (AFM), Auger electron spectroscopy (AES) and prepared with focused ion beam (FIB) for high-resolution transmission electron microscopy (HRTEM). Our results show that wear does not depend on the mechanical properties of different soot particles, but is closely related to their reactivity and the amount of defect sites. A new wear model for Otto soot is proposed.