A sliding door or window system includes a track. The track includes an outer housing; an inner housing within the outer housing; a guide body provided with the inner housing and configured to guide a sliding movement of a door or a window; and at least one adjustable body that is provided on the outer housing, at least partially within the inner housing, and fixed with respect to the inner housing in a vertical direction, the at least one adjustable body configured to change a height of the inner housing with respect to the outer housing by rotating, such as to change a height of the guide body.