These axle sliders fit over the nuts or into the large allen head hole on the axle so the outside diameter of the slider is supported against the axle block or fork leg to give the best rigidity. They are tied together with a 3/8 solid aluminium tie rod. One end is locktited and the other screws into a ss threaded insert for strength and longevity. (Excludes Skid Knobs as shown in picture)