Hydraulic tank for a bicycle, comprising: - a first wall; - a second wall opposite to the first wall and configured to place the tank in liquid communication with a hydraulic cylinder; - a side wall that extends between the first wall and the second wall; - an elastically deformable membrane operating between the first wall and the second wall and defining inside the tank a compensation chamber having a volume variable between a maximum volume defined in a condition of maximum expansion of the compensation chamber and a minimum volume defined in a condition of minimum expansion of the compensation chamber; wherein the membrane comprises: - a perimeter fixing portion that is a membrane portion which is fixed to the tank arranged outside of the tank and not subjected to deformation during the change in volume of the compensation chamber; - a thrusting portion of the membrane configured to move and deform inside the tank during the change in volume of the compensation chamber and configured to act on the brake liquid provided in the tank; and - a perimeter inlet portion of the membrane inside the tank arranged at an inlet region of the membrane inside the tank and arranged between the perimeter fixing portion and the thrusting portion, wherein in the condition of minimum expansion of the compensation chamber the thrusting portion is completely arranged between the perimeter inlet portion of the membrane and the second wall of the tank; characterized in that in the condition of maximum expansion of the compensation chamber the thrusting portion is completely arranged between the perimeter inlet portion of the membrane and the first wall of the tank. - a first wall; - a second wall opposite to the first wall and configured to place the tank in liquid communication with a hydraulic cylinder; - a side wall that extends between the first wall and the second wall; - an elastically deformable membrane operating between the first wall and the second wall and defining inside the tank a compensation chamber having a volume variable between a maximum volume defined in a condition of maximum expansion of the compensation chamber and a minimum volume defined in a condition of minimum expansion of the compensation chamber; wherein the membrane comprises: - a perimeter fixing portion that is a membrane portion which is fixed to the tank arranged outside of the tank and not subjected to deformation during the change in volume of the compensation chamber; - a thrusting portion of the membrane configured to move and deform inside the tank during the change in volume of the compensation chamber and configured to act on the brake liquid provided in the tank; and - a perimeter inlet portion of the membrane inside the tank arranged at an inlet region of the membrane inside the tank and arranged between the perimeter fixing portion and the thrusting portion, wherein in the condition of minimum expansion of the compensation chamber the thrusting portion is completely arranged between the perimeter inlet portion of the membrane and the second wall of the tank; characterized in that in the condition of maximum expansion of the compensation chamber the thrusting portion is completely arranged between the perimeter inlet portion of the membrane and the first wall of the tank.