The formation/decomposition of several compounds from the pyrolysis of tire wastes is compared in three different types of equipment. The types of laboratory equipment consist of a Pyroprobe, where the secondary reactions are minimized, and a horizontal pyrolysis furnace, where the cracking is severe. The yields obtained in both types of equipment are compared with those previously obtained in a fluidized bed reactor. On the other hand, the kinetic severity function (KSF) has been proposed as a measure of the cracking undergone by the tars produced. This paper focuses on the production of semivolatiles from tire wastes.