Monday, October 31, 2022

Dahon MuSP: Outward Folding Handlepost and External Cable Routing

The Dahon MuSP is a really nice drop bar folding bike that I assembled back in 2018. It's a rarely used bike, but it is always available as an option if you need to transport a folded drop bar bike to another location.

As shown below, when folded, it can be placed on the backseat of a car, or in the boot if the boot is large enough. On this Dahon MuSP, I chose an inward folding handlepost for a more compact folded size. Most of the time, it works, but it can also be rather awkward during folding.

The problem with the inward folding handlepost with a drop bar is the difficulty of actually folding the handlepost and drop bar, without the saddle or other parts of the bike getting in the way.

Another issue is that the shifters protrude from the folded bike quite significantly. For storage it is fine, but it barely fits in the backseat of the car, as the shifters are already touching the windows.

Folded Dahon MuSP on the backseat of a car. Shifters are right up against the window.

After much consideration, I decided to try a more conventional outward folding handlepost for this drop bar folding bike. Although the folded size would be wider, at least it would be shorter and perhaps easier to place into the car.

New outward folding T-shaped handlepost on the right, just a tiny little bit taller. Shorter ones are practically impossible to find.

The only difference is the direction of the joint, which determines whether it folds inwards or outwards.

Uses a simpler sliding safety lock instead of a rotating catch. Non-branded.

New outward folding handlepost is a little heavier at 503 grams.

New height is about 297 mm from the base.

For reference, the previous inward folding handlepost is a bit lighter at 494 grams.

It is a bit lighter because it is slightly shorter at 295 mm.

New outward folding handlepost installed on the Dahon MuSP!

The locking lever indicates the direction which the handlepost will fold down.

The handlepost swap is a straightforward and easy modification, as I have done it so many times on so many folding bikes.

Next, I also wanted to service some of the parts on the Dahon MuSP. One of the other problem that I faced was the wear and tear on the rear brake outer casing during folding.

Due to the internal cable routing, the rear brake outer casing will slide in and out of the frame during folding. As the hole on the frame has sharp edges, repeated folding will damage the outer casing, even when I fold and unfold the bike carefully. I have tried adding some plastic guides but they are not effective.

Damage to the rear brake outer casing at the frame hole area. Cuts and scratches on the outer plastic layer.

Prior to assembling this Dahon MuSP, I did not know that internal cable routing would be a problem for a folding bike. Although internal cable routing looks clean and nice, it is not so suitable for folding bikes. The United Trifold does a better job of internal routing, but it still has some limitations.

My solution is to change the cable routing to an external type, even though the frame is not designed for external routing. There are no external cable guides, so I have to create some.

Upon removal of the rear brake outer casing, I found that some places have cracked completely, exposing the coiled structure inside. 

Stick-on cable guides to save the day! Basically stick the backing onto the frame and use the C-clip to hold the outer casing or hose in place.

Initial placement of the stick-on cable guides, under the frame for better appearance. Same location as traditional external cable guides.

Near the seat tube, the cable guide will route the rear brake outer casing smoothly towards the Ultegra rear brake caliper.

Previously, the Di2 Junction B was placed inside the frame. With external cable routing, Junction B has to be placed on the outside, similar to how it is done on the Fnhon DB12.

The cables used to run internally through the frame joint, but they have since been moved to the outside.

This was the internal metal cable guide that protected the outer casing and Di2 wire across the frame joint during folding. It comes with the Dahon MuSP, but it is no longer necessary.

Here is how it looks, with an outward folding handlepost and external cable routing. Although the folded size is wide, it is also shorter than the previous setup.

When folded down, the end of the drop bar will stop against the front tire. If the handlepost is shorter, the drop bar will be able to clear the tire for an even more compact fold.

The modification has been completed, but a few days later, I noticed that the stick-on cable guide has been detached from the frame. The cable guides are pasted onto the frame with double sided tape, unfortunately it is not strong enough.

When folded for storage, this bend puts a lot of stress on the stick-on cable guides. In this position, the outer casing will detach the cable guide located underneath the frame after a few days.

First I tried using better 3M double sided mounting tape, but it was still not strong enough. The tape remains on the frame and on the cable guide, but the sticky part shears off due to the load from the bent outer casing. I considered using super glue or epoxy, but worried that the paint may come off instead.

Finally, after many different trials, I shifted the stick-on cable guides to the side of the frame, to better withstand the forces exerted by the outer casing. Also, a cable tie has been added to the stick-on cable guide to strengthen the connection and prevent the mounting tape from shearing off.

Front cable guide shifted from underneath the frame to the side to withstand the forces from the bent outer casing.

Middle cable guide undergoes the highest force, and needs to be reinforced with a cable tie to prevent it from coming off the frame. Rear cable guide is fine.

Final stick-on cable guide setup, which is still going strong after a few months.

External cable routing can be seen around the main frame. Not as aesthetically pleasing as internal cable routing, but more practical.

Looking good! The bike has a 1x11 speed Ultegra Di2 setup.

Latest bike specifications, with a 46T front chain ring and 11-32T cassette, for a 32 - 92 gear inches gearing.

Weight of this folding bike is about 9.7 kg inclusive of pedals and kickstand. Not really lightweight, as the frameset, wheelset and saddle are rather heavy.

On the other hand, if you start with a lightweight mini velo frameset such as the Java Freccia, the end result would be 3 kg lighter!

Wednesday, October 26, 2022

Focus Paralane: Phase 2 Assembly Completed

After finally getting the 12 speed Dura-Ace crankset, I can complete Phase 2 of the 12 speed upgrade to the Focus Paralane. Previously I had all the new 12 speed components except the crankset.

Dura-Ace R9200 12 speed crankset, with 50/34T chain rings.

Crankset beside a new PRO handlebar, which will be installed on the Cervelo Aspero gravel bike.

On the Focus Paralane, when I use a normal road crankset, I need a 1 mm spacer to have enough clearance between the chain ring and the chain stay.

The groupset is finally completed! Seen here with the Dura-Ace R9250 front derailleur.

View of the full bike with complete Dura-Ace 12 speed Di2 groupset!

Other than the crankset, I also took the chance to change the pedals. Previously I was using the XTR M9020 Trail pedals, but I needed it for another bike. So, I swapped the pedals on this bike for the newer XTR M9120 pedals, which are an updated version of M9020.

XTR PD-M9120 Trail pedals, at 393 grams for the pair. Weighs 21 grams more than M9020.

Dura-Ace and XTR! Best of the best.

What you see here is the older R9100 left crank arm with 4iiii power meter. 
Colour matches the R9200 crankset well.

As an all-weather commuting road bike, it sometimes gets caught in heavy rain as shown here.
Not to worry, just blow dry it with a fan.

High end components are often built with rust resistant materials, such as carbon, titanium, aluminium or steel with corrosion resistant coatings. Therefore, using Dura-Ace or Ultegra components on a commuting bike is what I prefer, as I get to use good components as well as minimizing the maintenance needed after rain.

With Phase 2 completed, the Focus Paralane has been fully upgraded from a 11 speed to a 12 speed Di2 drivetrain. However, as you will see from the upcoming posts about the Focus Paralane, there are more changes coming up.

This 12 speed Dura-Ace groupset will not stay on the Focus Paralane for long, as I have another bike project coming up that will require some of these Dura-Ace components.

Sunday, October 23, 2022

Focus Paralane: Dura-Ace 12 Speed Crankset R9200

On the Focus Paralane all-weather commuting bike, I had already upgraded most of the groupset to a 12 speed Dura-Ace system. Only one component was missing, and it was the 12 speed crankset. Due to production delays, I was not able to get the crankset at the same time as the rest of the components.

During Phase 1 of this upgrade, all the components have been changed to the latest Dura-Ace R9200 groupset, except for this crankset. Even so, there is no issue with using the older R9100 crankset in the 12 speed drivetrain, as they are mostly compatible, although you may not get 100% of the function.

Now that I have this 12 speed R9200 crankset, I can complete the upgrade in Phase 2 of this project.

Unboxing the new Dura-Ace R9200 crankset! New packaging design for Dura-Ace.

I chose the 50-34T chain ring combination, and a crank arm length of 165 mm. According to my own experience and also bike fitting, this length is good for me.

Most of the box is actually just air, as the crankset has a shape that takes up quite a bit of space.

Dura-Ace R9200 crankset!

Right crankarm with chain rings and chain ring bolts weigh 482 grams.

Right crankarm only is 341 grams, quite a bit more than the previous 9000 and R9100 construction.

One change to the spindle is the addition of a plastic cap inside, to prevent water from making its way through the spindle into the crank arm on the other end, which can cause corrosion from the inside.

Hollowglide 50T outer chain ring is 107 grams.

Aluminium 34T inner chain ring is 30 grams.

4x aluminium chain ring bolts are 5 grams in total.

R9200 left crank arm! Glossy finishing.

Super shiny and free of scratches when new.

Left crank arm, at 165 mm length weighs 197 grams.

New shorter crank arm fixing bolt is 3 grams. This is packed separately in a small paper bag, don't throw it out accidentally!

In total, this Dura-Ace R9200 crankset weighs 682 grams. This is quite a bit heavier than the previous generation R9100 crankset, which is just 610 grams! The old crankset weighs 72 grams less and is 10% lighter, which is a huge difference for Dura-Ace.

What I understand is that the additional weight comes from thicker walls for better strength and durability. The rigidity is probably improved as well from the extra material.

That said, a normal cyclist like me will not be able to put out enough power to detect any difference in stiffness. If you are looking for a weight weenie crankset, this R9200 crankset is not ideal, as there are other options that are lighter.

Nevertheless, it would complete the 12 speed Dura-Ace groupset on the Focus Paralane, despite the weight increase.