The gears connection presents a natural and necessary backlash which is transmitted to the shafts. A particular care in the assembly allows to keep such value within 15’-20’. For particular applications, where the standard backlash should be further reduced, it is possible to reach a maximum value comprised between 5’-7’. It is important to remember that an excessive backlash reduction could induce the transmission to be blocked due to the interference between the gears. Furthermore, a too tight backlash would cause friction phenomena and consequently an efficiency reduction as well as an heating of the transmission. The gears backlash tends to increase according to the wear ratio of the components, that is why after various running cycles we can logically expect an higher value than the value taken before the startup. Finally it should be reminded that, due to the axial components of the transmission forces, the backlash measured under load can be different than the value taken when the bevel gearbox is unloaded. In case a very high precision is requested, it is advisable to mount shrink disks, both on the output and on the input shafts, because among standard couplings it is the only one ensuring a minimum backlash for the mounting on the machine.