Type 2 Port Di2 has a 6mm hole to allow a Di2 cable to pass through the headtube of an RTD. It will require a 6mm Di2 bung. The devil is in the details… could Shimano Ultegra Di2 R8100 actually be a better buy in the real world? Our Media Once the system has been set up and shifting fully dialed in, it keeps running smoothly, all the time. You do not have to re-index Di2 systems or replace the shift cables. Ever.

If you’re building a new Di2-equipped bike there are a couple of things you’ll need to decide. We’ve already published a post on what components are available and how to select them. In this post, we look at figuring out how to route the Di2 wires through your frame so that you can put it all together. Type 3 Port Gear Cable allows has a cable stop, stopping the gear or brake cable housing for the bare inner cable to run internally through the frame. The difference is, once again, small, but the pedalling experience is slightly less smooth through the pedal stroke than I’ve felt with either Dura-Ace or Ultegra Di2 (which are standard-setters). Every time I’m building a Di2 bike I think about the components to use, and what length wires I need. While selecting the components may seem trivial, there are still plenty of things to keep in mind. This is by far the cleanest and most used setup on modern frames. It hides as much of the Di2 wiring as possible, making your bike look as clean as it can, and it improves aerodynamics slightly over a more external setup.Here, the throw-to-piston compression ratio is more linear (as it was for previous generations of Shimano disc brake groupsets). This means that comparatively more aggressive pulling of the levers is needed to achieve the same braking force, especially in the earlier phase of the action. The crankset and chainrings use Shimano’s Hollowtech II construction, whereby each crank arm is forged in two pieces and then bonded together.

It’s also a good idea to select a slightly longer wire for the seatpost battery. At some point you will want to be able to take out the entire seatpost to do maintenance, a system reset or cleaning and it’s nice being able to do this without having to stretch the Di2 wire and possibly damaging the connector. You can determine the seatpost wire length as follows: There are new hydraulic brake calipers too, and I recommend using them. Not only has the rotor-to-pad clearance improved, but they also feature new bleed ports which make bleeding your brakes a lot easier. You can buy these parts either as a kit of two shift levers and brake calipers or buy everything separately.You can use any of the two top ports on the shifters, in any way you like. In the image above the battery wire is connected to the middle port on the right shifter. Want to use the top port for that? Sure. Want to connect the battery to the left shifter? Go right ahead. An 11-36t non-series cassette (CS-HG710-12) is also available for those who require an even easier gear. This means there’s no cable routing to worry about from the shifters to the derailleur and battery system. The 105 Di2 levers also miss the customisable hood-top buttons seen on the more expensive groupsets, but unless you’ve already grown to rely on them, this is hardly a deal-breaker.