If you have an internal battery charger (ISMBCR2), you already have the tool that you need to customize the way your Di2 bike works. Plug one end into the port on the handlebar gear display, and the other end into a USB port on a PC. The E-Tube Project customization software is available at http://e-tubeproject.shimano.com
E-Tube project software can let you control several aspects of how the bike functions like which shift button does what, how quickly the bike shifts across multiple gears when you hold a button down, it can even let you turn a left shifter into a Fox iRD suspension control unit. In the Synchro Shift customization part of the software, you can adjust the default gear maps and make them your own. You can even reverse shift direction. Maybe you have an injured right hand … use a left shifter and have it control the rear derailleur instead. The great thing about E-tube Project and Di2… is the options and customization is endless and you can try and test to find an option that you maybe never even thought of.
Most riders find that one of the two default maps is perfect without any changes. If that happens to be S2, you can move that map over to the S1 position and call it your normal Synchro Shift mode. Then S2 becomes available for you to create something special that you can easily switch to on the fly by double pressing that button on the gear display. Here are two ideas for custom Synchro Shift maps:
Race Day: The large chain ring is a more efficient driving gear because of its larger diameter. The chain doesn’t have to deflect as much in order to wrap around a larger gear. It’s a small difference, but when seconds count, it can pay to maximize your driving efficiency. A racing Synchro Shift map could have the bike shift back up to the big chain ring as soon as possible after cresting a climb. That would mean that the bike would only use the two largest cogs on the cassette while riding on the small chain ring. By the third shift, the bike would climb right back up to the more efficient chain ring. There are still thirteen gear steps across the range, but now the most efficient gear combinations will take priority over a smooth shift up to the large ring. Just double press that button on the gear display on race day to switch over to race mode.
Mud Riding: The 2x11 mountain bike groups are designed to be ridden fully cross-chained in the large chain ring, large cog combination without any trouble. However, in especially muddy conditions, you may find that the drivetrain makes a bit more noise in this big-big gear combination. A rainy day custom Synchro Shift map might not let the bike ever shift into the big-big gear combination. It would still have thirteen gear steps across the entire range, it would just drop to the smaller chain ring one gear earlier. If you find yourself out on the trail in the rain, simply double press the button on the gear display and keep on riding.
Options are endless. You are in control. E-Tube Project is the software that lets you customize your Di2 to exactly how you want it.