The invention relates to a bicycle frame consisting of a rear triangle (t) which is joined to a front quadrilateral structure (c) of tubular elements, comprising a coupling element (A) which is common to both. The top of the coupling element is joined to an upper tube (4). In addition, the rear triangle (t) is equipped with upper tie-rods (3), lower tie-rods (7) and a curved closure element (2) which covers the rear wheel of the bicycle. The axis (e2) of the aforementioned coupling element (A) is approximately coplanar with the axis of the upper tie-rods (3), forming a comfortable angle (a) in relation to the axis of the upper tube (4) that is equal to or greater than 120°: a>120°.