Grid of pre-MS models with M_ZAMS from 2 to 14 M_⊙, by steps of 1 M_⊙, with Ω_ini ∝ M_ZAMS (i.e. models described in Sect. 3.3, solid blue lines). Two birthlines (without rotation and with the higher Ω_ini) are plotted (solid black lines). The dashed line indicates the ZAMS of Ekström et al. (2012) and dotted lines correspond to iso-radius of 0.1, 1, 10 and 100 R_⊙ from left to right. Equatorial surface velocities on the ZAMS are indicated (in km s^-1) at the end of each track. Dot-dashed red lines indicate isochrones of 2 × 10⁵, 5 × 10⁵ and 2 × 10⁶ yr from top to bottom.