We are using the AE spindles. What we do is install a 4-40 helicoil in the kingpin hole and then a set 5/8 long 4- 40 setscrew is installed. The pivot balls thread onto the setscrew on top and bottom and clamp to the spindle. The ball rotates nice and freely inside the pivot. It is twice as strong as a standard kingpin set up and alot more smooth.
