We present a study of the mechanical unfolding pathway of five different oligomers (alpha-peptide, beta-peptide, delta-aromatic-peptides, alpha/gamma-peptides, and beta-peptoids), adopting stable helix confotinations. Using force probe molecular dynamics, we identify the determining structural factors for the-unfolding pathways and reveal the interplay between the hydrogen bond strength and the backbone rigidity in the stabilization of their helix conformations. On the basis of their behavior, we classify the oligomers in four groups and deduce a set of rules for the prediction of the unfolding pathways of small foldamers.