Originally Posted by
TugaDude
I will throw this into the mix. This is from Sheldon Brown's website. He is long gone but his wisdom about bikes is still alive and well.
[size=13px]External-cam skewers use a curved plastic washer between the cam and the toothed metal washer that presses against the dropout.[/size]
The result is that the exposed-cam type provides very much less clamping force for a given amount of hand force on the lever.
I haven't had seen an external cam QR with a plastic washer in long long time. Are these a thing?
And while I can understand you need more hand force on external cam, as long as you can still exert enough force to clamp sufficiently, then well, your wheel is clamped sufficiently.