Another thought I had is, doesn't the kingpin add another point of stability/lock during smiths/feebles? Whereas if only the hanger touches the rail it's more prone to slide out of it?
I can see that being the case on ledges, but on round bars I could see the kingpin getting in the way and decreasing stability
I can see that being the case on ledges, but on round bars I could see the kingpin getting in the way and decreasing stability