The tire has a plurality of radially outer rubber components defining a radially outer surface (S1) exposed to fluids having a relative displacement with respect to the rotating tire. At least one radially outer component has projections, the projections being defined by first sides (2) and second sides (2') of unequal length. The first sides (2) have a greater length, delimiting therebetween an angle .alpha. ranging from 5.degree. to 60.degree. and forming at their intersection an apex (P). The projections protrude by a height (h) from the radially outer surface (S1) from which said first and second sides originate, the height (h) ranging from 0.2 to 100 micrometers. In more than 75% of the projections, any plane tangent to the first side (2) of the projection cuts the radially outer surface (S1) at an acute angle.