A motorization mechanism for a wheel of a landing gear assembly, including an input gear driven by a motor-reducer unit; a pendulum element, carrying two intermediate gear wheels driven in rotation by this element, with the intermediate gear wheels having synchronized rotation blocking mechanisms such that the two intermediate gear wheels can be simultaneously engaged or simultaneously released. The angular displacement of the pendulum element around its rotation axis is limited by a first and a second adjustable stop. These adjustable stops are set so that when the pendulum element comes into contact with an adjustable stop, the blocking mechanism of the intermediate gear wheels is freed, whereas it is engaged when the pendulum element is in the neutral position. This pendulum assembly faces a cog wheel that is capable of driving the hub of the said wheel.