Originally Posted by
Wilfred Laurier
I believe the strength of the hollow axles is comparable to solid axles because (a) in bending, the material near the outside diameter of the axle provides much more strength than the material closer to the inside, and (b) even if the hollow axle is slightly weaker, the skewer fills that space and adds the same amount of strength as the amount of metal missing from the axle. Unless you have exotic Ti or (*shudder*) aluminum skewers, which are both generally weaker materials than most steels for a part of the same geometry.
Maayyybe the QR axle lends a bit of support to the hollow axle if the latter bends enough, but I mostly think people overestimate the amount of strength/stiffness contributed by the "core" of a solid axle. It isn't much, otherwise we'd be riding bikes made out of solid rods rather than tubes.