Saturday, February 11, 2017

Avanti Inc 3: Alfine 11 Di2 Drop Bar Conversion Part 2

Continuing from Part 1 of this project, which is to convert the Avanti Inc 3 to a drop bar bike with Alfine 11 Di2, here are the rest of the components that are required.

The drivetrain system has been settled, with the new Alfine 11 Di2 hub and rear wheel, new 28T Gates rear sprocket and also the 115T Gates CenterTrack belt.

The other components that are required are the shifters, brakes and motor unit to activate the shifting inside the rear internal hub. As I want to have a drop bar bike with hydraulic disc brakes, the only shifter that is currently compatible with Alfine 11 is the non-series ST-R785 shifter. This is a road Di2 shifter that is integrated with a hydraulic brake lever. For more pictures and details, check out this earlier post where I studied the ST-R785 shifter in more detail.

ST-R785 Di2 road shifter integrated with hydraulic brake lever. Rather heavyweight due to the full aluminium bracket. For comparison, the new Dura-Ace ST-R9170 weighs only 316 grams/pair.

As the entire brake system will be changed, from the current Deore M615 hydraulic brake lever and brake calipers, there is a need to get new brake calipers and set up the whole brake system from scratch. This means installing the brake hose and bleeding the whole brake system.

This BR-RS785 brake caliper is the recommended brake caliper to go with the ST-R785 shifters

Low profile road hydraulic disc brake caliper, using the traditional Post Mount system, not the new Flat Mount standard

No banjo fitting for this brake caliper for a low profile look.

With the brake system components settled, next is the electronic components. As I am converting the bike from mechanical shifting to electronic shifting, I will need to get some electronic components. I have set up a few Di2 bikes previously, so this is quite straightforward for me.
Dahon Boardwalk Ultegra Di2
Dahon MuEX Ultegra/XTR Di2
Wheelsport Fantasy Ultegra Di2
Merida Scultura 5000 Ultegra Di2

New battery mount is required. A long battery mount is used and will be fixed to the bike using the water bottle cage mounts.

MU-S705 Motor Unit, will be fixed to the Alfine 11 Di2 hub to activate the shifting inside the hub. The yellow ring is the seal.

The splines that will engage with the Drive Plate on the hub. This unit has been pre-programmed to work with 11 speed Alfine Di2.

After installing the yellow ring to create a watertight seal around the Drive Plate area

Weighs 140 grams for this Motor Unit. Di2 wire will plug into the hole as shown at the bottom.

Wiring up all the Di2 components to test out, before installing onto the bike. The digital display, SC-S705 is from the Dahon Boardwalk a few years ago.

Wiring diagram for this Alfine 11 Di2 setup. Quite simple as there are fewer components than the road Di2 setup.

Everything worked fine even before any firmware updates. The plan is to share 2 external Di2 batteries across the 3 Di2 bikes that I currently have. The Merida Scultura 5000, Dahon MuEX, and this Avanti Inc 3.

The system is then connected to the Di2 SM-PCE1 box to update the firmware and also customize the settings.

Updating the firmware for all the Di2 components

It is possible to re-program the Motor Unit to work with either the 8 speed or 11 speed Alfine Di2 system

There is a fine-tuning function for adjusting the Motor Unit, in case there is some problem with the shifting. Otherwise, the factory setting will be fine.

A new drop bar is required to convert this bike from flat handlebar to drop bar. As weight is not the main concern, while durability and all-weather ability is more important, I opted for an economical FSA aluminium drop bar, in my preferred compact shape.

FSA drop bar (42cm width) that is wider than usual (40cm), in order for better control during wet weather. Same concept as on cyclocross bikes.

Flat top that may be more comfortable for holding

Over 300 grams for this handlebar, which is 50% heavier than the lightweight FSA K-Force carbon drop bar that I am using on the Merida Scultura 5000 and Wheelsport Fantasy Mini Velo.

One downside to using this Avanti Inc 3 frame and modifying it to a road bike style is that the top tube length of the Avanti Inc 3 bike is quite long. In fact, it is about 25mm longer than the Merida Scultura 5000.

Therefore, I decided to compensate for the longer top tube by using a shorter stem.

80mm Controltech stem

Looks very similar to the stock stem on the Merida Scultura 5000

Lightweight at only 112 grams

As a preview for Part 3, where the installation of all the new components will take place, here is a wheel weight comparison.

Weight of stock Alfine 11 (mechanical) rear wheel, without sprocket or disc rotor

Weight of new Alfine 11 Di2 rear wheel. Lighter by about 250 grams, mainly from the rim and spokes.

In the third part of this project, all the components will be installed onto the bike. Stay tuned for the updates and the pictures!

Part 3 here

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