Bicycle frame, which consists of a rear triangle (t) joined to a front quadrilateral (c) of tubular elements, with a common coupling element (A) for the two, which is joined at the upper part with an upper tube (4) and the rear triangle (t) consisting of upper braces (3), lower braces (7) and the sealing element (2), which is curved and covers the back wheel of the bicycle, and the shaft (e2) of the coupling element(A) being approximately coplanar with the shaft of the upper braces (3) forming a comfort angle (α) with respect to the shaft of the upper tube (4) of equal value to or greater than 120°: α>120°.