A method for the manufacture of a fiber-composite article for a bicycle frame or other bicycle component uses an outer mold configured to define an outer surface of the fiber-composite article and an inner mold configured to define an inner surface of the fiber-composite article. The method comprises: securing in the inner mold a supportive armature for a space-filling mandrel, the mandrel being configured to occupy a space within the inner surface of the fiber-composite article during lay up and curing of the fiber-composite article; forming the mandrel by injection molding a solidifiable fluid into the inner mold, around the armature, the solidifiable fluid being configured to form a solidified, molded material; applying a fiber composition to the mandrel; securing the mandrel with the fiber composition in the outer mold; heating the fiber composition in the outer mold to form the fiber-composite article and concurrently heating the solidified, molded material. In this manner, the fiber composition is compressed into the outer mold due to expansion of the solidified, molded material.