Shimano Ultegra R8170 rear derailleur cage lock

Cage lock mechanism for Shimano Ultegra DI2 R8170 rear derailleur.

This mechanism allows the derailleur cage of the R8170 rear derailleur to be locked in a forward position. Its purpose is to remove tension on the chain, which allows the rear wheel of the bicycle to be removed more easily. The mechanism locks the derailleur cage at 105 degrees from its native resting position. It has been tested only with the R8170 rear derailleur, but it may fit other Shimano road rear derailleurs.

To use, first position the mechanism over the rear derailleur body. Align the mechanism flush around the cylindrical body of the rear derailleur. Push forward the derailleur cage until the stop screw on the derailleur cage can be fit into the hole of the mechanism and the post of the mechanism can fit into the slot in the derailleur cage. Gently let the derailleur cage pull back. The mechanism will rotate with the derailleur cage until it jams into a surface on the derailleur body.