Originally Posted by
MNebiker
I'm actually surprised that the hollow skewer-type axles hold up under all the weight and impacts like they do. I have had to replace a couple of bent ones, but never had one come in broken. Back in the day - when I was a kid with a paper route my rear carrier mounted to the rear axle. I would sling two heavy canvas newspaper bags over the rear carrier. No problem with the carrier mounts, but the heavy load would snap the axle inside the hub 2 or 3 times a summer. I kept a spare part on hand and got pretty good at rebuilding the coaster brake assembly.
Originally Posted by
CliffordK
For bending, there are engineering reports indicating the hollow tube is nearly as strong as a solid bar.
A lot more of the strength of the QR axle vs solid axle depends on the materials and heat treating.
I have broken one QR skewer. It was an older Campy NR skewer. I was towing a trailer (chainstay hitch). But, moving the trailer around a bike rack, somehow I caught the skewer clamp end, and twisted it while clamped tight, breaking the skewer.
Otherwise, so far no problems with the skewers, including some trailer towing using a skewer hitch.
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.