Sunday, September 16, 2018

Dahon MuSP: Assembly Begins

In the first post about this Dahon MuSP folding bike, one of the requirements was for a blue wheelset. The overall colour scheme for the bike is thus black with blue accents. Other than the blue Wheelsport Smart 1.0 wheelset, it will look nicer if I can find some blue bits to add some colour to the bike.

However, blue parts are hard to find! Most of the custom colours are red, silver, black or silver. Very few blue parts are available. I managed to find some blue Litepro chainring bolts, to use on the front single crankset.

For this bike, other than the blue wheelset and the blue chainring bolts, I wanted to change the seatpost clamp and the headset to blue colour. This would be similar in idea to how I wanted to add red colour to the Dahon MuEX last time.

There are only a few sources with blue parts on Taobao, and you will not know if they really have it in stock, until you actually order it. Therefore I just have to try my luck and place the order...

Blue seat post clamp is available! Looks very much like the Dahon design which is good.


Looks good on the black frame. Although it will look better if the logo is removed...

Blue headset shown in the top row, with the Litepro headset shown at the bottom row.

The blue headset is from some generic brand with no logo. The construction is of an older design, which has more parts as compared to the Litepro headset which is much simplified. The part that can actually be seen is only the blue headset cover, therefore I mixed and matched the two headset to get the best combination that matches both the frame and the fork.

With the blue headset cover installed! Good contrast with the black frame and handlepost.

Frame, fork and handlepost installed, along with the blue headset cover and seat post clamp.

At this point in time, I was actually still waiting for the blue Wheelsport wheelset to be available as it was out of stock, which is why I could not start some parts of the assembly yet. However, I could install some other parts that are not directly dependent on the wheelset.

Ultegra R8000 brake calipers installed at the rear of the frame, using the dedicated caliper brake mount.

The brake calipers are also installed on the front fork, also using the dedicated caliper brake mount.

Before installing all the components, it is a good idea to connect up the Di2 components to make sure they are working properly. This is especially important since the internal routing will make it more difficult to troubleshoot if something does not work.

Di2 wiring layout on the Dahon MuSP. Note that the wireless unit and Junction A are actually placed in between the left and right shifters, which is unconventional.

In this layout, the 1000mm, 150mm, 300mm, 700mm Di2 wires are fully internal routed, while the 1400mm Di2 wire is partially internal routed through the main frame. As shown below, the 1000mm Di2 wire, wireless unit and 150mm Di2 wire are fully hidden within the handlebar.

Full Di2 layout tested on actual components to check if they are working properly. No problem!

Shown here is the right side bar end. The 1000mm Di2 wire (peeping out from the handlebar) comes from the left side shifter, through the handlebar, and is connected to the wireless unit. The short 150mm Di2 wire will be connected to Junction A.

Before pushing the wireless unit into the handlebar, it is first wrapped in sponge to prevent rattling inside the handlebar. Might be difficult to get it out next time...

The 150mm Di2 wire is then connected to Junction A. The other 300mm Di2 wire will pass through the hole at the handlebar, and run along the outside of the handlebar, up to the right shifter.

Once again, connecting everything to make sure it is working properly. Remember to install the Controltech stem before you install the shifters!

At the same time, I also connected the Garmin Edge 510 to the Di2 system, to display the selected gear. It works fine!

Now I know that the handlebar area of the bike is working fine, the next step is to wire up the rest of the bike. More specifically, connecting the Di2 rear derailleur, battery and Junction B together, before linking up with the handlebar.

This part is quite challenging, as it also requires the internal routing kit to help pull the cables and wires through the frame. I started with the 700mm Di2 wire, which is the one that links the Di2 rear derailleur with Junction B, and is routed internally through the right side seat stay.

Routing this Di2 wire from the seat stay side should be easier, as the hole at the seat stay side is small, while the frame hole near the joint area is bigger. It is always easier if the cable/wire exits from a larger hole.

View from the frame joint, looking back towards the seat tube and seat stays. It seems that the seat stay and main frame is not connected internally, but it actually is, through a small hole as seen on both sides of the seat tube.

Routing the Di2 wire through the small hole between the seat stay and the main frame is quite tricky, luckily I had an internal routing kit which uses a strong magnet to help guide the wire along the correct path.

The 500mm Di2 wire links the external Di2 battery to Junction B, which will be located internally inside the main frame. This wire will enter the frame through the hole for the rear brake cable.

At the other end, the long 1400mm Di2 wire will enter the main frame near the head tube area, and exit at the frame joint. Same path is taken for the rear brake cable.

After much work, the Di2 wires can be connected at the frame joint area! The two wires from the left comes from the battery and the rear derailleur, while the one from the right is connected to the handlebar area.

Once again, the components are tested to make sure they are working at this stage. Once done, the Junction B needs to be stored inside the frame, at the rear part of the main frame (near the seat tube).

In order to prevent rattling sounds, I will need to prevent Junction B from hitting the inside of the frame. I wanted to wrap Junction B in sponge, but I found that it does not fit into the hole after wrapping it in sponge. The other way is to stuff sponge inside the frame, to act as padding along the internal walls of the frame.

Junction B inserted into the frame, in between the sponge. The brake cable will also run through this hole, beside the sponge and Junction B.

All these internal routing takes a lot of time and effort, especially since this frame is not designed for internal Di2 wiring. I would prefer not to do it again, as it is quite a lot of trouble.

More assembly to be done! To be continued in the next post.

Wednesday, September 12, 2018

Dahon MuSP: Handlebar Setup for Di2

For the Di2 setup on the Dahon MuSP, it will be mostly an internal routing setup. The stock Dahon MuSP rear brake cable and rear derailleur cable are internally routed through the frame, giving a clean appearance.

Using the same concept, the new rear brake cable and also the rear derailleur Di2 wire will be routed internally through the frame. How about the cable routing at the front of the bike?

The usual set up on a road bike is to have a Di2 Junction A situated under the stem, with the shifter Di2 wires connected to this Junction A. This is the stock condition on the Canyon Endurace.

However, this is not a conventional bike, and so the usual Di2 wire routing is not advisable. On the Dahon MuEX, which is also a folding bike, there is a display screen on the handlebar, so the shifter Di2 wires will be connected to the display.

Also, in keeping with the internal routing concept, I would like to keep the Di2 wiring as neat as possible, which means hiding it internally where possible. With that, I considered something that I have never tried before, which is to run the Di2 wire inside the handlebar!

The concept is to hide Junction A inside the bar end for a clean look, and this is made possible by the new type of Junction A as shown below. Other than that, the wireless unit, EW-WU111 will also be hidden inside the handlebar. Finally, I will use a Garmin display to show the selected gear on the Garmin screen! This setup will maintain the neat appearance and yet allow the selected gear to be displayed.

In order to run the Di2 wires inside the handlebar, there will need to be some holes on the handlebar, so that the Di2 wires can be connected between the shifters and Junction A. I thought of buying a PRO handlebar with pre-drilled holes, but they were quite expensive and did not have the size that I needed in stock.

I came across a Youtube video showing how to drill holes in the handlebar for Di2 wiring. This might sound unsafe, but the area where the small holes will be drilled are not under high stress, and so from my point of view it is safe. Obviously this will void your warranty, so do it at your own risk. Lastly, don't do it on a carbon handlebar, as it is more risky.

Using the Youtube video as a guide, I did my own DIY internal routing on the handlebar!

FSA Vero Compact road handlebar, 40cm wide. Weighs 309 grams which is much heavier than a carbon handlebar that is around 200 grams.

Time to drill the holes at the end of the drop bar! For this 1x11 speed Di2 setup, I actually only need to drill one hole on the right side. However, as I want to control the Garmin with the hidden buttons on top of both the left and right shifters, I decided to also connect up the left shifter. This also gives the option of customizing the function of the shifting buttons, such as using the right shifter button for shifting up, and the left shifter button for shifting down, much like the SRAM eTap system.

Clamping the handlebar before drilling a hole. Start with a small drill bit to fix the hole position first, before changing to a larger 6mm drill size.

Drilled hole after removing the burrs

The edges of the holes are also taped up to help prevent the Di2 wire from being damaged by the edge of the hole.

With a similar hole drilled at the other end, this DIY internal routing handlebar is done! It is actually quite easy once you know the technique and have the right tools. By the way, this is the underside of the drop bar, which is normally under compression load and so it is not a danger to have a small hole drilled there.

As the handlepost is a T-shaped type, a stem is needed to link the handlepost to the handlebar. This is the exact same Controltech stem which I used last time on the Dahon Boardwalk.

Weighs 96 grams for this pair of aluminium stem

This stem converts the 25.4mm diameter of the T-shaped handlepost to the 31.8mm diameter of handlebars, while allowing reach and height adjustment at the same time.

The normal Litepro stem requires a 25.4mm diameter handlebar, which is not so common nowadays. Therefore, using this stem allows most road handlebars to be used, which increases your options greatly.

For internal routing through the handlebar, an internal type Di2 Junction A is required. This is quite new, and it is the first time I am using this type of Junction A. The other types of Junction A are the EW67 (used on Dahon Boardwalk and Merida Scultura) and the 3 port EW90 (used on Merida Scultura and Canyon Endurace).

Internal type of Junction A, EW-RS910.

This Junction A can be installed at the bar end of the drop bar, or inside the frame (if the frame is designed for it).

If used at the bar end, the bar tape will be wrapped on top of it. The mode button and the charging port can also be found on the exposed part. If you have an internal Di2 battery, you will need to charge it using this port.

All the parts that are included with this Junction A set, including those for internal frame mounting which I will not need.

Parts required for left and right side. The left side parts is just to make the bar end look similar to the right side, it is not compulsory. There is even a dummy wire (left side of picture) to wrap under the bar tape, to make the grip feel similar to the right side.

Weight of Junction A plus the other small parts weigh 25 grams.

Before installing the Di2 wires into the handlebar, I will first need to connect up the whole system to make sure it is working properly. That will be done in the next post where the bike assembly will start!

Wednesday, September 5, 2018

Dahon MuSP: Di2 Battery Placement and Wiring Layout

Once I decided to install an electronic shifting system on the Dahon MuSP, the next question was, where would the Di2 battery be installed? There are internal type and external type of Di2 batteries, and I need to see which one is more suitable for this frame.

For a start, this Dahon MuSP frame was never designed for Di2 wiring, let alone internal wiring. However, since I already have the frame in hand, I can experiment to see how to wire up the whole Di2 system.

My first thought was to use the internal Di2 battery and try to fit it somewhere within the frame, since there are openings in the frame and also sufficient space within the frame.

 Shimano Di2 internal battery, BT-DN110. It is long and slim, unlike the external type battery that I used on the Dahon MuEX.

As I did not have an extra internal Di2 battery on hand, I could not check if the battery can fit into the frame or not. What I did have was the battery dimensions which I found online. I tried to find an item of similar dimensions, and use it to test fit it into the frame. Coincidentally, I found that one of my screwdrivers has almost the exact same dimension as the internal Di2 battery!

Internal Di2 battery size is about 16mm in diameter, and about 160mm in length.

The diameter of this screwdriver is almost the exact diameter of the internal Di2 battery!

The length is almost the same too, although this is less important for testing the fitting.

The idea is to slot the battery inside the frame, through the holes at the joint area. Let's take a look at the joint area first.

The holes that are found at the frame joint. Although the joint is big, the holes are quite small...

The metal sleeve is first removed from the frame. This metal sleeve guides and protects the outer casing when it crosses the joint area.

Using the screwdriver to test, it is just unable to go into the hole, by a small margin.

Unfortunately, based on the testing, the internal Di2 battery is unable to fit into the frame through the holes at the joint area. Even if it just manages to fit inside, it is also not recommended as it will be almost impossible to get it out the next time, unless there is sufficient space to pull it out.

Therefore, I have to drop the idea of using the internal Di2 battery on the Dahon MuSP. It would be a really clean setup if the battery can be stored internally, but it is not possible for this frame design.

The only way is to mount the Di2 battery externally, same as on the Dahon MuEX. The best location will be behind the seat tube, where it is relatively well hidden and does not interfere with the folding of the bike.

I removed the external Di2 battery and battery mount from the Dahon MuEX to test the fitting on the Dahon MuSP frame, as shown below.

Ideal location of the external Di2 battery. However, the two curved parts of the frame seems to get in the way.

It will protrude from the top of the seat stays slightly.

At this position, still able to open the lever to remove the battery from the battery mount.

Just for record, the battery plus battery mount weighs 102 grams.

With the battery location decided, the next step is to think how to attach the battery mount to the frame. Last time, I made a custom adapter so that I can velcro the battery mount to the seat tube. This time, it will be the same concept.

With a scrap piece of aluminium, I cut the shape to the required design, and tapped 2 x M4 thread holes for mounting the battery mount. This aluminium piece weighs about 50 grams.

Spray painted black colour to blend in with the frame. Two short M4 bolts are needed as I did not drill and tap the holes fully.

On hindsight, I should have designed the adapter in 3D software, and 3D printed the part. It would save me a lot of hands on effort, be lighter in weight, and probably fit better to the frame. That is what I would do if I had to design an adapter the next time.

Mounting the battery mount onto the aluminium adapter.

With the battery secured in place. The cutout under the battery mount is for the velcro strap to go through.

Due to the limited space around the seat tube, this is the only location available for the velcro straps. Cannot be higher up or lower down, this is already the optimized position.

View of the battery location from the back. Well hidden by the tall seat stays on either side.

Sufficient clearance to open the lever to release the battery from the mount. I also added a piece of rubber in between the seat tube and the aluminium adapter for additional grip.

Although this method may not seem very secure, it is actually good enough. Apart from being extensively tested on the Dahon MuEX, which uses essentially the same design, I also tested this Dahon MuSP on a long ride of 60+ km and there was no issue at all.

The battery may sometimes shift slightly to the left or right side, but it will not slide downwards as the two velcro straps plus the rubber provides sufficient grip to hold the battery.

With the battery location finalized and confirmed, the complete Di2 wiring layout can be made. This is a new arrangement which is not conventional, and which I am trying out for the first time. The good thing about the Di2 E-Tube system is that the components do not need to be wired up in any specific order. As long as you have the components located somewhere within the layout, it will work fine.

Di2 wiring layout on the Dahon MuSP

Referring to the Di2 wiring layout above, let's take a look at the conventional and also non-conventional areas. For the rear of the bike, between the rear derailleur, battery mount and Junction B, it is a standard layout. The Junction B will link up the battery, rear derailleur and the front of the bike. This is quite standard and similar to on the Dahon MuEX, except that this time the Junction B will be placed internally instead of behind the seat tube.

As for the front of the bike, the usual layout is to link the two shifters to Junction A, with one wire linking up Junction A to Junction B. In my case, a different layout was used.

From the diagram above, the left shifter will be linked to Junction A, by running the Di2 wire internally inside the handlebar. The wireless unit will be installed in series, also inside the handlebar. Also note that this Junction A is an internal bar end type, which I will show more in another post.

The wire then runs from Junction A, out of the handlebar and into the right side shifter, before another wire runs from the right side shifter to Junction B. This simplifies the wiring layout and avoids duplicate wires running up and down the same area.

Weight of the six Di2 wires used in the wiring layout above.

New challenges in this Di2 wiring layout:
1) New type of Junction A, which goes into the end of the drop bar instead of being exposed outside.
2) Running Di2 wire internally through the drop bar.
3) Hiding the wireless unit inside the drop bar.
4) Internal wire routing through the frame.

Some of these points have not been elaborated on, but it will be shown in the next post.

Thursday, August 30, 2018

Dahon MuSP: Di2 Shifter and Rear Derailleur

One of the highlights of this new Dahon MuSP is the electronic shifting setup. It is not the first time that I am setting up Di2 electronic shifting on a folding bike, as I have already done it before on the Dahon Boardwalk and Dahon MuEX a few years ago. However, what is new here is internal cable/wire routing for this Dahon MuSP frame, which increases the challenge quite a bit.

Prior to getting these electronic components, I already had the Dahon MuSP frame in hand, in order to study how to set up and assemble the Di2 components onto this frame. I have a plan in mind, but this will be shown in a later post. Only after that was I able to get the required Di2 components, as the set up is rather unconventional.

For this post, let's take a look at the main electronic components, which are the Di2 rear derailleur and the Di2 shifters.

The Ultegra Di2 R8050 rear derailleur is new, as it is a Shadow type road rear derailleur, much like the Dura-Ace R9150 version on the Canyon Endurace. At the same time, it is also styled to look similar to the mechanical version, which is the Ultegra R8000 rear derailleur.

Ultegra Di2 RD-R8050 rear derailleur. Dark grey colour to match most bikes.

Rather strange combination of black and silver bolts here, especially as the black bolt does not match the dark grey colour.

Silver B-tension screw, and the two High and Low limit screws. Easily accessible and visible.

Di2 port is relatively well hidden, behind the main structure and on top of the motor unit. Saver unit also shown here.

View of the cage set. Made of aluminium inner and outer plates.

Inner link shown here with a rough texture, and looks like it is made of glass fibre reinforced plastic.

Weighs 239 grams for this Di2 rear derailleur, which is about 40 grams more than the Dura-Ace Di2 version.

This Ultegra Di2 rear derailleur weighs 40 grams more than the Dura-Ace Di2 rear derailleur, but it is about half the price, with a similar performance as the motor unit looks to be the same. The rational, and more value-for-money choice here would be the Ultegra version, as it is more cost effective compared to the Dura-Ace version.

These shifters are the electronic shifting, mechanical braking version. In other words, it is designed for Di2 shifting, and will be paired with the mechanical road caliper brakes. Although the trend now is for hydraulic disc brakes, it is not suited for this folding bike, which is why I am still using the mechanical brake version.

Ultegra Di2 ST-R8050 electronic shifters with mechanical braking.

Textured rubber hood for better grip and a more high end appearance.

The electronic shift levers have been reshaped and enlarged slightly for better ergonomics.

The tactile feedback of the buttons have also been improved, to give a stronger click feeling, much like the Dura-Ace shifters.

On this Ultegra version, there is even the extra button on top! Previously it was only available on Dura-Ace shifters, but now even Ultegra grade Di2 shifters have it which is really useful.

Hole at the front of the shifter for holding the cast head of the brake inner cable. Also note the grip adjust screw at the left side.

Small hole on the left side is for the brake inner cable to pass through, while the larger brake outer casing will slide into the holding area around the small hole.  

Grip adjust screw located here, which is used to adjust the lever position.

As this shifter will be used by a rider with small hands, the grip adjust screw is turned all the way in, to minimize the reach of the brake lever.

Comparing the position of the lever before and after adjusting the grip adjust screw.

Hidden under the rubber hood are also 3 Di2 ports, which is increased from 2 previously.

This pair of Di2 shifters weigh just 303 grams! Much lighter than the Ultegra 6800 mechanical shifters which weigh 424 grams per pair.

For this new generation of shifters, the hood shape has been adjusted so that regardless of mechanical or Di2 shifting, mechanical or hydraulic braking, the hood should feel similar in the hand. Let's try to compare this Ultegra Di2 shifter with mechanical braking to the Dura-Ace Di2 shifter with hydraulic braking, which is found on the Canyon Endurace.

Comparing the shifters side by side. The hydraulic shifter on the right has a slightly bigger head, but the body size looks similar.

Similar curves on the brake lever, buttons and hood

Appearance comparison from the front. As always, the Dura-Ace lever always looks much more glossy.

Once again, the Ultegra Di2 shifter has practically all of the functions of the Dura-Ace Di2 shifter, except that it weighs a bit more. If you can accept this, then the Ultegra shifters is a much better deal as it is much cheaper than the Dura-Ace shifters.