We present the modeling of SINFONI integral field dynamics of 18 star forming galaxies at z \sim 2 from H \alpha line emission . The galaxies are selected from the larger sample of the SINS survey , based on the prominence of ordered rotational motions with respect to more complex merger induced dynamics . The quality of the data allows us to carefully select systems with kinematics dominated by rotation , and to model the gas dynamics across the whole galaxy using suitable exponential disk models . We obtain a good correlation between the dynamical mass and the stellar mass , finding that large gas fractions ( M _ { gas } \approx M _ { * } ) are required to explain the difference between the two quantities . We use the derived stellar mass and maximum rotational velocity V _ { max } from the modeling to construct for the first time the stellar mass Tully-Fisher relation at z \sim 2.2 . The relation obtained shows a slope similar to what is observed at lower redshift , but we detect an evolution of the zero point . We find that at z \sim 2.2 there is an offset in log ( M _ { * } ) for a given rotational velocity of 0.41 \pm 0.11 with respect to the local Universe . This result is consistent with the predictions of the latest N-body/hydrodynamical simulations of disk formation and evolution , which invoke gas accretion onto the forming disk in filaments and cooling flows . This scenario is in agreement with other dynamical evidence from SINS , where gas accretion from the halo is required to reproduce the observed properties of a large fraction of the z \sim 2 galaxies .