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

I like the clean smooth look of the outer link, more than the edgy design of the Dura-Ace rear derailleur.

Ultegra weighs 262 grams, compared to just 216 grams for the Dura-Ace.

Practically the same internal components are used for Dura-Ace and Ultegra Di2. Limit screws and button positions are the same.

Same design as the Dura-Ace

Pivots are not covered with stickers like what is found on the Dura-Ace version.

On the Ultegra, both inner and outer cage are made from aluminium instead of carbon fibre. The cage is also longer than that of the Dura-Ace.

Moving on, I also got a new Ultegra Di2 front derailleur for the Focus Paralane.

Ultegra Di2 FD-R8150 front derailleur

Comes with the same metal sticker for frame support and the Di2 wire guide.

Weighs 111 grams, a bit more than the Dura-Ace which weighs just 95 grams.

Construction is essentially the same as the Dura-Ace version.

Ultegra uses a steel chain guide to save cost, which adds a bit of weight. Dura-Ace uses aluminium to save weight.

Close up look

Front view

Rear view

Ultegra Di2 has the same performance as Dura-Ace, but at half the price as the surface treatment and material cost is not as high. Instead of using carbon fibre and aluminium everywhere, the construction is changed slightly such that aluminium and steel can be used instead to lower cost, at the expense of a bit more weight.

Unless you absolutely have to get the greatest and lightest components, I would not hesitate to use and recommend Ultegra Di2 if your priority is to have great electronic shifting performance.

Ultegra Di2 rear derailleur installed!

Still using the same Dura-Ace 11-30T 12 speed cassette.

Ultegra Di2 front derailleur installed

Still using the Dura-Ace R9200 crankset, as the Ultegra R8100 crankset was not in stock yet.

New Ultegra Di2 rear and front derailleurs, with the Dura-Ace C36 wheelset from the Aethos.

Using 105 R7000 left crank arm with 4iiii power meter. As you can see there are many different series of components on the Focus Paralane.

Testing the new setup at Jurong Lake Gardens

There was absolutely no discernable shifting performance difference when I switched from Dura-Ace Di2 to Ultegra Di2 rear and front derailleurs. The smart money is on the Ultegra Di2 groupset which gives you all the performance at half the price of Dura-Ace.

In the next post I will show the new Ultegra R8100 crankset when it finally arrives, to complete the Ultegra 12 speed drivetrain on the Focus Paralane.