A pulley assembly for a continuously variable transmission in a vehicle, comprising a shaft having an axis, a supporting element rotatable about said axis, a first half pulley rigidly and rotationally connected to said supporting element, a second half pulley facing said first half pulley for defining a seat adapted to accommodate a belt of the transmission, at least one of the first and second half pulleys being longitudinally mobile with respect to the supporting element, and a clutch comprising a second supporting element connected to the shaft, a drum connected to the supporting element and accommodating the second supporting element, and a plurality of friction elements hinged to the second supporting element about respective hinge axes to selectively cooperate with the drum. In particular, the respective centres of gravity of said friction elements are located before the respective hinge axes with respect to a direction of rotation of the shaft which defines a forward running condition of the vehicle.