Tarmac SL8 Shimano Ultegra R8170 Di2 12s DT Swiss ERC 1400 35 DB Expo

The Specialized Tarmac SL8 Custom is a road bike with a carefully specified component build rather than a standard off-the-shelf configuration. It starts with a FACT 10r carbon frame paired with a Specialized carbon fork. This foundation is combined with 12-speed Shimano Ultegra Di2 electronic shifting, hydraulic disc brakes and a clearly identified selection of components.

The drivetrain uses Shimano Ultegra ST-R8170 Di2 shifters, an FD-R8150 Di2 front derailleur and an RD-R8150 Di2 rear derailleur, all within the 12-speed Ultegra family. Electronic shifting lets the rider select gears using the dedicated controls. The Shimano Ultegra FC-R8100 crankset has 52/36T chainrings and 172.5 mm crank arms. The double-chainring arrangement provides a choice of gearing for different riding rhythms and road profiles, while crank length is one of the measurements worth considering when assessing fit and riding position.

Braking is handled by Shimano Ultegra BR-R8170 hydraulic disc brakes. They complete the Shimano specification and provide a hydraulic braking system for controlling speed on the road. The fitted wheelset is the DT Swiss ERC 1400 35 DB, identified by its full model name to make this particular build clear. Together, these parts are central to the actual specification of the Tarmac SL8 Custom, rather than details assumed from a stock product listing.

Up front, the integrated Roval carbon handlebar measures 400 mm c-c and is paired with a 110 mm stem. These dimensions matter when considering hand position and reach, particularly on a bike with an integrated cockpit. A Prologo Dimension T4.0 saddle provides the seating contact point, while the Specialized carbon seatpost completes the listed finishing kit. The combination of the FACT 10r frame, Ultegra Di2 12-speed components, DT Swiss ERC 1400 35 DB wheels and equipment from Roval, Prologo and Specialized gives this Tarmac SL8 a distinct, fully specified Custom build.