The Shimano Ultegra RD-R8150 brings top-shelf Di2 electronic shifting to the midrange road groupset, delivering 58% faster actuation than the previous Dura-Ace generation. With SHADOW RD construction, integrated wireless, and support for 11–34T cassettes, it's the benchmark for precision and reliability in 12-speed road drivetrain performance.

Highlights

  • 12-speed Ultegra Di2 electronic rear derailleur
  • 58% faster shifting than previous-generation Dura-Ace RD-R9150
  • SHADOW RD low-profile design for quiet, chain-stay-clearance performance
  • Integrated Bluetooth and ANT+ wireless transmitter — no separate unit required
  • Wired and wireless Di2 communication with compatible levers
  • Built-in charge port (EW-EC300 compatible) with LED status indicator
  • Single cage length covers 11–34T cassettes
  • Precision sealed bearings in guide and tension pulleys
  • Compatible with Shimano E-TUBE Project app for personalised shift tuning

Di2 Electronic Shifting

The RD-R8150 uses Shimano's latest Di2 motor actuator technology to execute gear changes with exceptional speed and consistency. Electronic actuation eliminates mechanical cable stretch and mis-indexing, delivering the same precise shift feel in the first kilometre and the hundredth. The integrated E-TUBE port allows firmware updates, custom shift modes, and synchronisation with Di2 front derailleurs and third-party apps.

SHADOW RD Design

The low-profile SHADOW RD cage keeps the derailleur close to the dropout, reducing the risk of chain-stay contact on rough roads. Sealed precision bearings in both the guide and tension pulleys minimise friction and maintain smooth chain tracking across the full cassette range, even under fatigue or adverse conditions.

Wireless Connectivity

An integrated wireless unit transmits shift signals over both Bluetooth and ANT+, pairing with compatible Di2 shift levers and cycling computers without a separate EW-WU111 unit. The single SD300 port provides a wired connection point for additional Di2 components such as a junction or battery link, keeping the system flexible for various frame configurations.

Compatibility & Fit

The RD-R8150 is designed for 2×12-speed road use. It is compatible with Shimano Ultegra R8100 and Dura-Ace R9200 groupsets. Recommended cassettes are CS-R8100 and CS-R9200 (11–28T, 11–30T, or 11–34T). Compatible chains include CN-M9100, CN-M8100, CN-M7100, and CN-M6100. Mounting is conventional (direct mount and hanger adaptor configurations supported). Total drivetrain capacity is 39T with a maximum front chainring difference of 16T. Not compatible with mechanical or previous-generation Di2 (11-speed) levers.

Shimano Ultegra components are covered by a 2-year manufacturer's warranty against defects in materials and workmanship from the date of original retail purchase. This warranty applies to products purchased from authorised Shimano dealers and does not cover damage resulting from misuse, neglect, improper installation, or failure to follow Shimano's service guidelines.

For warranty support, return the item to Tune Cycles.

  • Shimano Ultegra R8100 series — 2×12-speed Di2 electronic rear derailleur
  • 58% faster actuation than previous-generation Dura-Ace RD-R9150
  • SHADOW RD low-profile cage design
  • Integrated Bluetooth and ANT+ wireless transmitter
  • Supports both wired and wireless Di2 communication
  • EW-EC300 charging port with LED battery indicator
  • 1× EW-SD300 port for wired Di2 component connection
  • Precision sealed bearings in guide and tension pulleys
  • Compatible with Shimano E-TUBE Project for firmware and tuning
  • Single cage length — fits 11–34T cassettes
  • Maximum cassette sprocket: 34T
  • Total capacity: 39T
  • Weight: approximately 262 g
SpecificationValue
SeriesUltegra R8100
Speeds12
Cage TypeSHADOW RD (single cage length)
Maximum Sprocket34T
Minimum Sprocket11T
Total Capacity39T
Maximum Front Difference16T
Pulley Teeth11T
Mounting TypeConventional
WirelessBluetooth / ANT+
Ports1× EW-SD300, 1× EW-EC300
WeightApprox. 262 g
Compatible CassettesCS-R8100, CS-R9200
Compatible ChainsCN-M9100, CN-M8100, CN-M7100, CN-M6100
ColourBlack
SKU SHM-IRDR8150E
Barcode # 4550170168520
Brand Shimano

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