A thorough evaluation of the mechanical behavior exhibited by fast crystallized propylene-1-pentene copolymers, synthesized in a broad range of 1-pentene compositions, is here described. Different mechanical magnitudes derived from loading, creep and unloading processes in depth sensing indentation measurements are correlated to structural features. Several ordered forms are able to be developed applying a fast cooling processing at the composition interval analyzed in these propylene-1-pentene copolymers. Moreover, either a single polymorph or distinct ratios of two crystalline lattices can be obtained, depending on comonomer content. Crystallinity as well as the type of existing crystallites play a critical role in the value of those mechanical magnitudes. An uncommon dependence of either crystallinity or stiffness on 1-pentene content is observed in these copolymers, associated with their capability of crystallizing in the trigonal form. (C) 2017 Elsevier Ltd. All rights reserved.