- 1). Open the Thule Ride-On or 523 Criterium adapter like a clam shell and slide it under the bottom of the round bar. Clamp the top of the adapter down on the top of the round bar. Place one adapter at each corner of the crossbars.
- 2). Screw the adapters together using the plastic wing nuts included with the adapter. Place the wing nut underneath the round bar and turn to the right to tighten.
- 3). Adjust the distance between the round bars using the Allen keys or Thule installation tool to loosen the attachment towers. Slide the cross bars to the needed distance apart.
- 4). Attach your sport rack to the Thule adapters on the round bars. Consult your rack's installation guide for proper installation on the adapters.
Source...