Proper alignment and function of the Shimano 9150 Dura-Ace Di2 Front Derailleur is crucial to both shifting performance and protecting your downtube from the force of this incredible electronic shifting system. When your frame doesn't feature a braze-on mount, you will need the proper derailleur clamp adapter. The standard polished Shimano clamp doesn't provide the proper set-up of the front derailleur, so Shimano offers this SM-AD91 Derailleur Clamp Adapter 9150 for the updated system.

Cast from stout aluminum alloy, this dark gray colored clamp is distinctive and cannot be mistaken for the polished version. Shimano offers the SM-AD91 in two downtube diameter options: 34.9mm, and a 31.8mm version that can be shimmed down for 28.6mm.