Ultra-fast 12-speed Di2 shifting - compact and smartly connected.

The Shimano Ultegra Di2 RD-R8150 Rear Derailleurs is the electronic heart of the 12-speed ULTEGRA R8100 groupset and combines the rear derailleur, control unit and wireless unit in one compact component. It offers the industry's very fast, precise shifting performance and controls all Di2 functions at the rear - including LED status display, pairing and adjustment mode.

The uniform cage length simplifies selection: The RD-R8150 accommodates 12-speed road bike cassettes with up to 34 teeth on the largest sprocket and offers a total capacity of 39 teeth. With the Auto-Trim function and SHIMANO Synchro-Shift (including Semi-Synchro support), the system intelligently adjusts gear combinations, reduces cross-chaining and ensures the chain is always routed optimally.

The rear derailleur is wireless-capable and houses the unit for wireless signal transmission, as well as the central function/pairing button with LED display. This allows you to check the battery status, pairing and adjustment mode directly on the rear derailleur. Operation requires a Di2 battery (e.g. BT-DN300), suitable EW-SD300 cables and the EW-EC300 charging cable (not included).

Important installation note: The rear derailleur is designed for Direct Mount. The Shimano axle unit for rear derailleur hanger is not included and must be purchased separately if required. Suitable axle unit:

Shimano number: Y3J198020
EAN: 4550170229375

Highlights:

• 12-speed Di2 rear derailleur: electronic shifting precision for modern ULTEGRA R8100 road bike setups.
• Integrated control unit: wireless function, charging port, function button & LED status display directly in the rear derailleur.
• Synchro-Shift & Auto-Trim: intelligent shifting logic for a clean chain line and optimally selected gears.
• One cage for everything: uniform cage length for cassettes up to 34 teeth - simplifying component selection.

Technical specifications:

• Brand: Shimano
• Groupset: ULTEGRA
• Series: R8100
• Model: RD-R8150
• Product category: electronic Di2 rear derailleur
• Application: Road / road bike
• Rear speeds: 12-speed
• Technology: Top Normal
• Recommended chain: HG 12-speed (Shimano Road 12-speed)
• Total capacity: 39 teeth
• Max. largest sprocket: 34 teeth
• Min. largest sprocket: 30 teeth
• Max. smallest sprocket: 11 teeth
• Min. smallest sprocket: 11 teeth
• Max. front difference: 16 teeth
• Functions: Auto-Trim, Shimano Synchro-Shift, LED status display (battery level, pairing, setup mode)
• Integrated unit: wireless interface, switch & charging port in the rear derailleur housing
• Compatibility: Shimano ULTEGRA R8100 12-speed Di2 systems
• Color: dark grey / ULTEGRA finish

Scope of delivery:

• 1 x Shimano Ultegra Di2 RD-R8150 Rear Derailleurs | 12-speed | electronic
• without axle unit / rear derailleur hanger
• Note: workshop packaging (without outer packaging)

Manufacturer's part no.: IRDR8150F | EAN: 4550170240967

The Shimano Ultegra Di2 RD-R8150 is the central shifting and control unit for your 12-speed Di2 road bike - compact, fast, precise and ready for modern, wirelessly connected road setups.