Set for installing a leaf (3) of a sliding door (1) provided with a wheel set (12) in a frame (2), the set including a leaf (3), a frame (2), a wheel set (12) and an aid (1), whereby the aid (15) includes supporting elements (17) that each define a support point (20) for the leaf (3), whereby the distance (D.sub.s) between the support points (20) is less than the thickness (D.sub.v) of the leaf (3) and whereby the aid (15) includes at least one connecting element (16) to fix the supporting elements (17) with respect one another.