LTWOO eRX Groupset: Front and Rear Derailleurs

Continuing from the previous post, where I showed the shifters and brake calipers of the LTWOO eRX groupset, here are the rest of the components.

Front derailleur is 140 grams, quite a bit more than 111 grams of the Ultegra Di2 front derailleur.

Similar linkage design as Shimano Di2 front derailleurs

Inner view, looks the same as Shimano Di2 front derailleurs.

I find that the corners of the motor housing look quite sharp, perhaps they can be rounded off a bit more.

LTWOO eRX 12 speed rear derailleur. Looks pretty good!

Also uses a similar link design as Shimano Shadow rear derailleurs.

Looks very much like Shimano Di2 rear derailleurs

Here is the port for connecting the electric wire. There is a little notch in the connector to ensure alignment.

Limit screws located at the bottom, both stop against the inner link.

Resin moulded Plate Member with visible fibres in the material, and covered with a clear coat.

Looks like a carbon outer plate on the cage?

Inside view, showing the relatively long cage with an aluminium inner plate.

Weighs 289 grams, a bit more than the Ultegra R8170 version. Can't complain given the price difference.

Other than the components, the groupset also includes the electronic parts required to link up everything. This LTWOO eRX system is semi-wireless, similar to Shimano. The shifters communicate wirelessly with the rear derailleur, while the battery powers both the front and rear derailleurs via wires.

Battery, charging cable, and two electric wires.

Charging cable which has a proprietary connector to the rear derailleur charging port, and is powered by a standard USB port.

Two ports available at the bottom of the battery, to be connected to the front and rear derailleur.

Two electric wires of 90 cm and 120 cm, for the front and rear derailleurs.

I did not assemble the LTWOO eRX groupset on any of my bikes, as I did not think it was better than the Ultegra Di2 groupset that I already have. After this study, I sold the groupset as I had no more use for it.

12 Speed Di2 Rear and Front Derailleur Comparison: Dura-Ace R9250 vs Ultegra R8150

Here is another comparison post, and a very important one at that. This may answer a common dilemma that many cyclists have: Should I get Dura-Ace or Ultegra components? As a rough guide, Ultegra components are about half the price of Dura-Ace, but nearly all the performance and just a little bit more weight, depending on the type of component.

In the previous post, I compared the Dura-Ace and Ultegra cranksets, and concluded that the Ultegra R8100 crankset is the better choice due to the very small weight savings of the Dura-Ace R9200 crankset.

Now, let's compare the Di2 rear derailleur and front derailleur of Dura-Ace vs Ultegra. Check out the differences and similarities, and decide for yourself! Let's start with the rear derailleurs.

As Di2 electronic components, the model numbers are as shown.

Dura-Ace Di2 12 Speed Rear Derailleur: RD-R9250

Ultegra Di2 12 Speed Rear Derailleur: RD-R8150

Dura-Ace Di2 rear derailleur on the left, Ultegra Di2 rear derailleur on the right.

Black glossy finish vs matte dark grey finish, see how it looks on the Focus Paralane.

Focus Paralane: Ultegra Di2 12 Speed Rear and Front Derailleurs

When I was building up the new Specialized Aethos lightweight road bike, I wanted to put Dura-Ace components onto the Aethos. However, it was too expensive to get another set of Dura-Ace components on the Aethos, when I already had one set on the Focus Paralane.

My solution is to move the Dura-Ace components from the Focus Paralane over to the new Specialized Aethos, then get a cheaper set of components for the Focus Paralane. Previously I splurged on Dura-Ace components for the Focus Paralane, because it was my only road bike which doubled up as an all-weather commuting bike. Also, Dura-Ace 12 speed was more readily available than Ultegra 12 speed at that time (early 2022).

Now that I have the Aethos as the pure road bike, I didn't feel the need to put the best components on the Focus Paralane. This was why I chose the 12 speed Ultegra Di2 components to replace the Dura-Ace Di2 components on the Focus Paralane.

I will be moving the Dura-Ace RD-R9250 rear derailleur and FD-R9250 front derailleur over, while I will not be transferring the Dura-Ace shifters and brakes as it is too troublesome to uninstall and reinstall them again on the Aethos. The hydraulic hose length might not be long enough which would require a hose change as well. I would rather do a fresh, hassle-free, Shimano J-Kit installation of new shifters and brake calipers on the Aethos.

Here are the new Ultegra Di2 rear derailleur and front derailleur!

Ultegra Di2 RD-R8150 12 speed rear derailleur

Specialized Aethos: Assembly Part 2 with Dura-Ace Di2 12 Speed Components

With the bottom bracket issue settled, now I can continue to assemble the Specialized Aethos. For the components, I am mostly using the Dura-Ace R9270 components which were previously installed on the Focus Paralane. I decided to use the Dura-Ace components on this Aethos, while I will install a new set of Ultegra 12 speed components on the Focus Paralane instead.

Dura-Ace Di2 RD-R9250 12 speed rear derailleur.

Focus Paralane: Phase 1 Assembly Completed

Phase 1 of the Focus Paralane 12 speed upgrade is finally completed! To be accurate, the upgrade was actually completed more than 6 months ago, but I only found the time to write about it now.

This is considered Phase 1 as the upgrade is not completed, as the new 12 speed Dura-Ace crankset is not yet available, so I am still using the older 11 speed Dura-Ace R9100 crankset. Since the pros are also using this older crankset with the new 12 speed groupset, I guess it works well enough not to be an issue.

Here are the pictures of the completed bike, with new 12 speed Dura-Ace components!

Dura-Ace R9270 hydraulic Di2 road shifters.

Focus Paralane: Dura-Ace Di2 Front Derailleur R9250

Next component to introduce for the 12 speed Focus Paralane would be the Dura-Ace Di2 Front Derailleur, FD-R9250. There are some noticeable differences with the previous 11 speed front derailleur, we shall see what they are.

2x12 speed Di2 front derailleur

Here it is! With 2-piece chain guides that are riveted together.

Focus Paralane: 2x11 Speed Drivetrain Installation

As a commuting bike, the Focus Paralane is nearly perfect, as it is a fast road bike with high end components. However, since I use it a a road bike for group rides as well, I find that the gear range is not quite enough. This is most apparent when riding down slope, as the highest gear (Front 40T and rear 11T) is 98 gear inches, which is not enough when riding fast down the slopes.

Therefore, if I am using it as a road bike for group rides as well, I need more gear range. There is already a wide 11-36T cassette on this bike, so I cannot use a wider range cassette without sacrificing the close gear steps. Best way is to install a front double system with two chain rings, to get the wider gear range and yet with close gear steps.

When I installed the Dura-Ace R9100 crank arms onto this bike, the chain rings were kept aside. Now, what I need to do is to just reinstall the chain rings onto the Dura-Ace crank arms.

Before that, I needed to check if this frame can accommodate a front derailleur properly. The stock Curana fenders had a cutout to avoid interference with the front derailleur, so with the SKS mudguards, there might be some issue.

Attaching the Dura-Ace FD-R9250 Di2 Front Derailleur to the front derailleur mount to check it out.

Canyon Endurace: Dura-Ace Di2 R9150 Front and Rear Derailleur

I first started using the Shimano Di2 electronic shifting system on the Dahon Boardwalk, with the Ultegra Di2 6770 groupset. From there, I have installed quite a few more Di2 systems on my bikes.

Dahon Boardwalk Ultegra Di2 6770
Dahon Boardwalk Ultegra Di2 6870
Dahon MuEX Ultegra/XTR Di2
Wheelsport Fantasy Mini Velo Ultegra Di2 6870
Merida Scultura 5000 Ultegra Di2 6870
Avanti Inc 3 Alfine 11 Di2

Once you have tried electronic shifting, it is hard to go back to mechanical shifting, as the shifting force is so light, and the buttons are easy to activate with just one finger.

The Canyon Endurace comes with the Ultegra Di2 6870 groupset, which is a great Di2 groupset. However, my intention all along was to upgrade the components to the latest Dura-Ace R9170 when they became available. Let's take a closer look at the Di2 rear derailleur and front derailleur to see how different it is from the previous generation.

For the rear derailleur, the main difference is the new construction design. From the double servo construction of previous road rear derailleurs, the latest R9150 Di2 rear derailleur is now using the Shadow construction of MTB rear derailleurs. This lowers the profile of the rear derailleur, reducing the amount which the derailleur sticks out from the side of the bike. You can see the design of the previous generations here.

Shadow construction used for the new Dura-Ace Di2 R9150 rear derailleur. Servo motor is located at the rear and looks really small.

Weighs only 197 grams, including the motor! Lightweight materials are used throughout the whole component.

Extra link to shift the pivot of the derailleur rearwards, allowing for a Shadow construction.

E-tube port for connecting the Di2 wire is hidden behind, for a minimal profile.

B-tension screw and the two limit screws are located just beside the motor, and are adjusted using Allen keys and not screwdrivers.

Very industrial design with the cover of the motor following the shape of the internal parts of the motor and gearbox.

Tall toothed guide pulley to improve shifting speed and accuracy

Short toothed tension pulley to minimize running noise when cross-chained.

Carbon inner and outer plates minimize the weight but increases the cost considerably.

Bottom side of the derailleur. Rivets are capped with a black sticker for a nicer appearance.

Upper side of the derailleur. The saver unit has been moved from the bottom (previous generation) to the top, probably due to the change to Shadow design. This is the position during normal operation.

If the derailleur receives an impact from the side, the saver unit will give way and disengage from the motor, as shown here. This prevents damage to the motor unit.

With the change of construction, this rear derailleur looks and operates quite differently from the previous generation of Di2 rear derailleur. More findings will be shared after installation to the bike.

As for the front derailleur, it remains largely unchanged from the previous generation, at least in terms of external appearance.

Dura-Ace Di2 R9150 front derailleur. The little black plastic piece shown at the side is the cap for covering the Di2 wire.

The Di2 wire connection is now facing the rear of the bike.

To use the cap, first insert the Di2 wire into the cap, and use it to insert and remove the Di2 wire from the front derailleur. This cap also protects the port from water and dirt.

Front derailleur weighs 102 grams, not much heavier than a mechanical front derailleur.

The main appearance surface of the front derailleur

Inside surface of the front derailleur

Rear end of the front derailleur, where the rivets can be seen

Front end where the black clamp bolt can be seen

The grey inner link seems to be made of titanium, as it is not attracted to a magnet and does not look like aluminium.

The biggest surprise for me is how lightweight the Dura-Ace Di2 front and rear derailleurs are. With a combined weight of only 300 grams, they are super lightweight, and it includes the motor!

Wheelsport Ultegra 2x11 Speed: Part 10 - Ultegra 6800 Mechanical

The Wheelsport Fantasy 2x11 speed mini velo that I have is currently using the Ultegra 6870 2x11 speed Di2 groupset, which was inherited from the Dahon Boardwalk folding bike that I had previously. On the other hand, the Merida Scultura 5000 road bike is using the Ultegra 6800 2x11 speed mechanical groupset.

My plan is to swap the groupsets for these two bikes, so that the Di2 groupset goes onto the road bike, while the mechanical groupset goes onto the mini velo. I started with disassembling the mechanical Ultegra 6800 road shifters from the road bike. The Ultegra rear derailleur was already removed from the road bike previously, while the front derailleur was exchanged from a band type to a brazed on type.

With the Ultegra 6800 shifters, RD and FD ready, the building process for the mini velo can begin! First, the Di2 components were taken off the mini velo and put to one side. These Di2 components will be installed onto the Merida road bike later on.

Since the Wheelsport Fantasy mini velo is already using the Ultegra 6800 crankset, and an 11 speed cassette, it is actually not too difficult to disassemble and assemble the bike since it is already half done.

Started by removing the Di2 components from the mini velo 

Reinstalling the parts that are required for mechanical shifting. The cable guide that goes under the bottom bracket, and the cable adjust bolts for adjusting the cable tension for the shifter cables.

Cable guide goes under the bottom bracket...

...while the cable adjust bolts go onto the outer casing stoppers that are located under the downtube

New polymer coated shifter inner cables and outer casing for smooth and light shifting

Ultegra 6800 2x11 speed mechanical shifters from the Merida road bike!

Ultegra 6800 11 speed short cage RD also from the Merida road bike

Ultegra 6800 front derailleur installed onto the custom FD mount for best performance

Road shifters installed, bar tape wrapped!

Ultegra shifters, FSA K-Force carbon handlebar, Ultegra road caliper brakes, Wheelsport Smart 451 wheelset

Full Ultegra 6800 drivetrain (with Dura-Ace cassette and chain)

View of the full bike! Ultegra 6800 groupset looks really good on this mini velo

The hand pump and the tool bottle mounting was rearranged as the Di2 batter mount has also been removed

Simple graphical guide for trimming the front derailleur with the new road shifters

Yet another project has been completed! The Wheelsport Fantasy mini velo has been successfully converted from Ultegra 6870 Di2 to Ultegra 6800 mechanical shifting. It still rides and shifts beautifully, especially with this lightweight build. In fact, it rides better and faster than the Dahon Boardwalk folding bike that I previously had as this mini velo frame is much more rigid and does not flex when pushing the bike hard.

Finally, the full specifications and weight of this bike! Lightweight at less than 7.8 kg without pedals.