Bring electronic Di2 shifting to your existing rim brake road frame without replacing your whole bike. This carefully curated kit pairs Ultegra-level ST-R8150 Di2 shifters — the only 12-speed Shimano lever that supports both wireless shifting and rim brakes — with the proven 105 R7150 Di2 drivetrain to deliver fast, precise electronic shifting at the most accessible price point possible.

Highlights

• Ultegra ST-R8150 Di2 dual-control levers — 12-speed, wireless, rim brake compatible
• 105 RD-R7150 Di2 rear derailleur with integrated charge port and Shadow design
• 105 FD-R7150 Di2 front derailleur, braze-on mount, 45% faster front shifts vs previous generation
• 105 FC-R7100 Hollowtech II crankset — available in 50/34T or 52/36T, 160–175 mm lengths
• 105 CS-R7100 12-speed cassette, 11-34T, steel cogs with alloy spider
• Shimano 12-speed CN-M6100 chain with quick link
• BT-DN300 internal Di2 battery — approx. 2,000 km range per charge
• EW-SD300 wiring, EW-JC302 junction box and EW-EC300 charger included
• Synchro Shift and Semi-Synchro Shift modes configurable via E-Tube Project app
• Direct upgrade path from 10- and 11-speed Di2 systems

Electronic Shifting Performance

The R7150 Di2 system uses a semi-wireless architecture: the derailleurs connect to the BT-DN300 internal battery via EW-SD300 wire, while the ST-R8150 levers communicate wirelessly. The result is a clean, junction-free cockpit with no exposed cables running to the bars. Rear shifts are claimed to be 58% faster and front shifts 45% faster than the previous 11-speed Di2 generation. Synchro Shift mode lets the front derailleur change chainring automatically based on rear cassette position, keeping you in the optimal gear range at all times. All shift parameters — speed, multi-shift count, synchro mode — are tunable via the free E-Tube Project app.

Kit Components & Compatibility

The ST-R8150 levers are the only current Shimano 12-speed STI compatible with rim brakes, making them the essential choice for this build. They use Shimano's short-pull brake mechanism and accept standard Shimano rim brake calipers (BR-R7000 or equivalent — not included). The FC-R7100 Hollowtech II crankset requires a 24 mm Hollowtech II bottom bracket (sold separately). The CS-R7100 cassette fits Shimano 11- and 12-speed freehub bodies. The BT-DN300 battery mounts internally inside the seat post or frame down tube.

Compatibility & Fit

• Suitable for road frames with braze-on front derailleur mount (FD clamp adapter sold separately if needed)
• Rim brake calipers not included — compatible with Shimano BR-R7000 and equivalent short-pull rim calipers
• Bottom bracket not included — requires 24 mm Hollowtech II BB (e.g. SM-BBR60 or pressfit equivalent for your shell)
• Cassette requires Shimano 11- or 12-speed HG freehub body
• BT-DN300 battery requires internal routing via seat post or frame (min. 27.2 mm seat tube diameter typical)
• Compatible with E-Tube Project app (iOS & Android) for firmware updates and system configuration
• Chainring options: 50/34T or 52/36T; crank lengths: 160, 165, 167.5, 170, 172.5, 175 mm