An assembly for adjustably mounting a vehicle external mirror includes a first arm segment for securing to the vehicle, and a second arm segment for securing to the external mirror. An axle member is secured to one of the first and second arm segments and extends through an opening defined through the other of the first and second arm segments, the axle member defining a swivel axis therethrough and the first and second arm segments being pivotable and adjustably securable relative to each other about the swivel axis. A securing member is attached to the axle member for securing the first and second arm segments together about the axle member. A bearing brace having a fixed end is secured to one of the first and second arm segments and a free end extending from the fixed end, the bearing brace configured and secured so as to form a leaf spring. A plurality of teeth extend from one of the bearing brace and the other of the first and second arm segments. A plurality of grooves are defined in a surface of the other of the bearing brace and the other of the first and second arm segments. The grooves may receive the teeth in any of at least two different adjustable orientations to thereby adjustably secure the first arm segment to the second arm segment.