Core (continuous lines) and surface (dotted lines) rotation rates for models computed with and without an additional viscosity during the main sequence. These models do not include a braking of the surface by magnetized winds. The black and green lines indicate models with an additional viscosity of 1 × 10⁴ cm² s^-1 during the whole evolution and an initial velocity on the ZAMS of 8 and 10 km s^-1, respectively. The blue and red lines correspond to models without an additional viscosity during the main sequence, with an initial velocity on the ZAMS of 8 km s^-1, and an additional viscosity during the post-main sequence of 1 × 10⁴ and 1.1 × 10⁴ cm² s^-1, respectively.