Abstract: A vehicle external review-view mirror assembly having an extension and retraction mechanism for a telescopic arm support that connects a mirror head to a mirror mounting bracket is disclosed. The assembly comprises: a hollow outer arm extending from the bracket, an inner arm mounted to the head and extending into the outer arm for relative sliding movement out of and into the outer arm; a driving wheel rotatably mounted to the inner arm or the head; a driven wheel rotatably mounted to the inner arm and positioned within the outer arm at a location spaced apart from the driven wheel; and a toothed belt extending between the driving wheel and the driven wheel for power transmission between them. A pair of laterally spaced apart contact rollers are mounted coaxially with the driven wheel, the pair of contact rollers engaging spaced apart bearing surfaces depending from the outer arm.