Sunday, January 20, 2013

Journey of the Boardwalk: Part 25 - Ultegra Di2 (Part 1)

Hey! It has been quite a while since I have written about my Dahon Boardwalk. The reason is because I haven't been doing any modifications or upgrades to the Boardwalk. After "zhnging" the bike to 2x10 speeds, there isn't much more I can do. Or is there?

I recently went on an amazing cycling holiday in Taiwan with some LCSG folks, and it was super fun! You can read about it here. However, one of the discomforts I experienced in Taiwan was while we were cycling along the numerous slopes. The terrain at some places is such that you get upslopes followed closely by downslopes, then another upslope, and this repeats for many kilometres. However, the gradient and the distance, plus the strong headwinds, means that you cannot use momentum to help you out like on rolling hills (such as the Desaru slopes). As such, you will have to constantly change gears as you pedal up and down the slopes.

This repeated gear shifting, especially for the front shifting, makes your hands very tired from the constant operating of the gear levers. At that point, I thought that if we could utilize electronic shifting, it would be much easier!

This is a major project as I don't think I have seen anyone install a Shimano Ultegra Di2 electronic gear shifting system onto a folding bike before. I believe that very few folding bike frames can accommodate a Di2 system. So, is it possible to have a Dahon folding bike with Ultegra Di2?

Before I start the project, I first had to determine if my Dahon Boardwalk can be installed with the Ultegra Di2 system. From what I see, the major problem is the front derailleur (FD). Because of the bulbous size of the servo motor in the FD, the frame might interfere with the placement of the FD. I actually went to borrow an FD and installed it to see if it fits. I was glad to see that it fits (barely!).

The top of the FD just manages to clear the seat stay of the Boardwalk!

This small clearance also means that the Dahon Mu frames cannot install the FD due to the curved seat stay. Even the Vitesse frames cannot use this FD as the aluminium seatstay is larger in diameter. Having said that, the smaller Dura-Ace Di2 FD might fit, but it is hard to be sure without physically checking it.

In order to start this new project, I set out to read up more about the Ultegra Di2 system, and got the necessary parts. Let's take a look at the part list and the wiring diagram.

The part list for the Ultegra Di2 parts. These are only the electronic components (except the chain).

The sample wiring diagram. Internal and external routing uses slightly different components.

Let's take a closer look at the individual components.

Ultegra Di2 ST-6770 Shifters:

Each component comes in its own box!

The pair of Ultegra shifters

Textured rubber grip, with a smaller and improved hood shape

The two buttons for shifting. The button placement is similar to the current shifters, with the textured button (located on the brake lever) shifting to a lower gear, and the paddle at the back shifting to a higher gear. This can be reprogrammed if desired.

 Two electrical ports on the side of the shifter. One of it is used to connect to the handlebar wiring, the other is for auxillary shifters.

Ultegra Di2 RD-6770 Rear Derailleur:


The 2 limit screws at the bottom of the RD.

Ultegra Di2 FD-6770 Front Derailleur:

Two metal tabs that are provided, to be stuck onto the frame. These tabs are to help support the FD during shifting. Details to be shown during installation.

 Rear view of the FD

Ultegra Di2 Battery and Battery Mount:


Bottom of the battery, where it connects to the battery mount.

The short external battery mount. Originally designed to be mounted directly on frames with suitable M4 hole mounting point. I am using this as I have an idea how it can be mounted on my frame.

The battery mount comes in 3 different types: Internal (Long), for frames with internal routing. External (Long), designed to be mounted using the bottle cage holes. External (Short), as shown above, for frames with specially designed Di2 mounting point.

Ultegra Di2 Junction A (For Drop Bars):

This connects up the two L & R shifters and links it to the rest of the circuit. It also has a battery indicator and a button to initiate derailleur adjustments.

Ultegra Di2 Wires:

4 wires are needed to link up the system. The wires used are similar and interchangeable, with length as the only difference.

Comes in many different lengths! For my Boardwalk, I needed an extra long 1200mm wire to link up Junction A to Junction B.

The other wire lengths I got are 2 x 300mm, 1 x 500mm. These are standard lengths that come with the wiring set.

The wiring set includes standard wire lengths, Junction B, and battery mount. I did not get the package as I needed a mixture of internal and external parts, and different wire lengths. Thus I bought the wiring parts individually.

Ultegra Di2 Junction B:

Comes in two types. JC41 for internal routing, JC40 for external. The internal type is designed to fit inside the frame. The external type is mounted under the BB, and secured using the bolt hole for the BB guide.

 I got the internal type, as it is smaller and easier for me to find a place to mount. I cannot use the standard JC40 junction as my bike does not have the mounting.

 Junction B links up all the wires from the RD, FD, shifters and battery.

Ultegra Di2 Satellite Shifters (SW-R600), Optional:

This is an optional part, not necessary for the Di2 system. However, it is a very useful add on. This shifters can be mounted on the flat part of the drop bar. This gives a secondary shifting position even when I am holding the top of the handlebar.

The two buttons for up and down shifting. By default, the right button shifts to a lower gear. This can be changed by reprogramming the shifters.

The rear of the button, where it will be fixed onto the handlebar by cable ties.

Overall Parts for Ultegra Di2:

There are a lot of individual parts for the Ultegra Di2 system! All (except the optional satellite shifters) are required to make the entire system work.

In the next part of the article, you can see how I installed the Ultegra Di2 system onto my Dahon Boardwalk! It is not as straightforward as on a standard road bike, as there are many restrictions and limitations. Nevertheless, it is possible, and I like challenges! Stay tuned for the project updates.

Part 2 of the Ultegra Di2 upgrade is now up! Click here to continue reading.

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