Shimano Ultegra 6600 road bike gear shifters are connected to their respective derailleurs by a single cable. When a gear is shifted, tension on the cable causes the derailleur to pivot and transfer the chain to the next gear. Gear cables, also called derailleur cables, are swapped out periodically once the cable can no longer be adjusted effectively or the cable shows signs of fraying or other damage.

Shift the rear Ultegra gear shifter into its highest gear.

Squeeze the rear brake lever to reveal the gear cable hole on the side of the head of the lever. Pass the gear cable through the hole until it is fully seated. Release the lever.

  • Shimano Ultegra 6600 road bike gear shifters are connected to their respective derailleurs by a single cable.
  • Pass the gear cable through the hole until it is fully seated.

Route the gear cable through the drive-side cable stop, midway along the right, drive side of the bicycle frame down tube.

Pass the cable through the slot in the cable guide, on the underside of the bicycle frame.

Pass the gear cable through the protective housing that leads directly to the rear derailleur.

Grasp the tip of the cable and pull it beneath the rear derailleur.

  • Route the gear cable through the drive-side cable stop, midway along the right, drive side of the bicycle frame down tube.
  • Grasp the tip of the cable and pull it beneath the rear derailleur.

Locate the threaded nut at the rear of the derailleur. Turn the nut all the way into the derailleur, and then give it two turns counterclockwise.

Pull the end of the cable. Using a 5mm Allen key, tighten the pinch bolt, on the underside of the derailleur, onto the cable.

Use the rear Ultegra 6600 gear shifter and try shifting the derailleur onto the next sprocket over. If the derailleur fails to shift, turn the threaded nut at the rear of the derailleur counterclockwise once.

  • Use the rear Ultegra 6600 gear shifter and try shifting the derailleur onto the next sprocket over.

Try shifting the derailleur a second time. Continue to turn the threaded nut at the rear of the derailleur counterclockwise as needed until the derailleur shifts the chain onto the sprocket.

Shift the front Shimano Ultegra 6600 gear shifter into its lowest position.

Squeeze the front brake lever to reveal the gear cable hole on the side of the head of the lever.

Pass the gear cable through the hole until it is seated.

Thread the gear cable through the non-drive-side cable stop, midway along the left, non-drive side of the bicycle frame down tube.

Route the cable through the slot in the cable guide on the underside of the bicycle frame.

Pass the cable up along the seat tube and to the front derailleur.

Locate the threaded nut midway along the cable on the left, non-drive-side bicycle frame down tube.

  • Thread the gear cable through the non-drive-side cable stop, midway along the left, non-drive side of the bicycle frame down tube.
  • Locate the threaded nut midway along the cable on the left, non-drive-side bicycle frame down tube.

Turn the nut clockwise until it stops. Then rotate the nut twice in the opposite direction.

Pull the end of the cable tight. Using a 5mm Allen key, tighten the pinch bolt above the derailleur onto the cable.

Use the front Shimano Ultegra 6600 gear shifter to shift the derailleur to the large chain ring. If the derailleur fails to transfer the chain, turn the threaded nut midway along the cable counterclockwise once.

Try shifting again. Continue to turn the threaded nut counterclockwise until the derailleur transfers the chain successfully to the large chain ring.