For our Shimano Ultegra 6870 Di2 groupsets, you will need to choose five wire lengths for: shifters, down tube, front derailleur, rear derailleur and battery. Three configurations are available for battery location and wire routing, based on your frame compatibility:
- Internal wiring with internal battery. Diagram
- Internal wiring with external battery. Diagram
- External wiring with external battery. Diagram
Check your frame specifications to choose which configuration works best.
There are two junction box’s needed for completing the Di2 build. Junction A is located at the handlebars and Junction B is located either internally or externally at the bottom bracket area, depending on your frame specifications. Junction A three-port option is used for standard left and right shifters. If you are using Shimano’s time trial shifters, you will need the Junction A five-port option.
The battery mount is available in three configurations: Short External, Long External, and Long Internal. The Long versions are mounted using the bottle cage mounts, and the Short version is designed for Di2-specific frames with either a down tube or chainstay mounting location.
Note: Determine your wire lengths needed and to be safe, use the next length up to eliminate the possibility of stretching wires during installation.
How To Choose Your Di2 Groupset:
1. Determine if your frame uses an internal or external battery mount, and whether the wire routing is internal or external. (See the illustrations above for your specific configuration measurements.)
2. Measure from shifters to Junction A to determine shifter wire length.
3. Measure from Junction A to Junction B to determine down tube wire length.
4. Measure from Junction B to front derailleur to determine front derailleur wire length.
5. Measure from Junction B to battery location to determine battery wire length.
6. Measure from Junction B to rear derailleur to determine rear derailleur wire length.
For further assistance please feel free to give us a call at 1-800-688-8600.
This Shimano Ultegra Di2 6870 eight-piece kit includes: Shimano Ultegra Di2 6870 front derailleur, rear derailleur, shifters; Shimano Ultegra 6800 brakes, cranks, bb, cassette and chain. Also includes Di2 Power System: 6870 Di2 Wire Kits (6); Di2 Battery, junction box, charger and cable. Cassette ranges: 11-23, 11-25, 11-28, 12-23, or 12-25.
Front derailleur clamp, frame grommets and cable covers sold separately.