Neither is universally more durable — they fail differently rather than one clearly outperforming the other at the thicknesses typically used in luggage shells. Polypropylene tends to flex under impact and spring back to shape, which is why it’s popular for cases expected to take repeated knocks over years of handling.
Polycarbonate, used in Delsey’s Shadow range among others, is more rigid and holds its shape very precisely, which suits cases where dimensional accuracy against a strict sizer matters, though a sufficiently hard impact is more likely to crack a purely rigid shell than a more flexible one.
In practice, shell thickness and overall construction quality matter more than the base material choice — a thin polycarbonate shell and a thin polypropylene shell are both more fragile than a thicker version of either material, so comparing thickness and reinforcement within the material is more useful than assuming one material universally beats the other.
Last reviewed 26 August 2026