Bump map is not affected only my unwrapped faces I have unwrapped the faces where I wanna put my bump map (details of a pirelli's tire), the problem is that is affecting also the other faces even if I setted the image texture to clip. I scaled in UV editor the unwrap faces to let enough gap from the edge's border and the texture image.
I fixed a little bit by duplicate the rubber's material, added only on the second one the bump map and assigned this to selected faces, but in this way if then I will change some settings of the rubber's material (the first one) I have to copy every single new setting to the bumped material.