Originally Posted by
Koyote
.....As for me, my qr disc bike came with external cam steel skewers which worked just fine, though I did pretty promptly swap in some XT skewers -- just because I'm pretty persnickety about keeping the wheels attached to my bike. ......
Cams is cams. Internal, external doesn't matter. They' re simply ramps used to pull out one end of the skewer.
What does matter is the cam's rise, skewer strength. and the strength of the user. So stretch a skewer by X and the clamping force is Y.
That's true regardless of the skewer material, though one that's thinner or has a lower elastic modulus will need more rise to achieve the same tension. (something easily factored into the design).
What also matters to a degree is the material and dentation of the biting face.
However, we shouldn't be relying on the skewer to bite into the dropout for hold, that should come from the axle.
All we should expect from a QR is compressing the frame securely against the axle, where the hold happens. That's a fairly low ask and just about any skewer should deliver.